Papers by Ryan Cotterell
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| Challenge: | Language modeling is a core task in natural language processing. |
| Approach: | They propose to characterize leakage onto the set of infinite sequences by a measure-theoretic approach. |
| Outcome: | The proposed language model families are tight, meaning they will not leak . the proposed language models are based on the 'sequence leakage' hypothesis . |
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| Challenge: | Weir has defined a hierarchy of language classes whose second member (L2) is generated by tree-adjoining grammars (TAG), linear indexed grammars, combinatory categorial grammars and head grammars. |
| Approach: | They propose to extend Weir's mechanism of control to give a definition of controllable pushdown automata (PDAs) they propose to use a stricter notion of equivalence to allow for finer-grained comparisons than weak equvalence. |
| Outcome: | The proposed language classes are d-weakly equivalent to Weir's original two-level grammar, but not d strongly equivalent. |
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| Challenge: | linguistic typology is concerned with mapping out the relationships between languages with structural and functional properties. |
| Approach: | They propose a computational model which identifies known and new linguistic universals and uncovers them worthy of further linguistic investigation. |
| Outcome: | The proposed model outperforms baselines and knowledge base baselines. |
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| Challenge: | Byte-Pair Encoding (BPE) is a popular algorithm used for tokenizing data in NLP, but the underlying optimization problem that BPE seeks to solve has not yet been laid down. |
| Approach: | They propose an algorithm which is a 1/sigma*(1-e(-sigma))-approximation of an optimal merge sequence. |
| Outcome: | The proposed algorithm improves the runtime complexity from O(NM) to O(N log M) and the lower bound of the approximation is approx0.37. |
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| Challenge: | Existing studies have found that higher quality language models provide more powerful predictors of human reading behavior, but empirical support for the QP hypothesis is mixed. |
| Approach: | They propose to test the quality–power hypothesis by using surprisal language models to test their ability to predict eye tracking data. |
| Outcome: | The proposed model is based on a set of language models with a 'quality-power' hypothesis. |
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| Challenge: | Large neural networks in NLP produce real-valued representations that encode the bit of human language that they were trained on. |
| Approach: | They propose a kernelization of the recently-proposed linear concept-removal objective and propose to remove linear subspaces from the representation space. |
| Outcome: | The proposed kernelization protects against the ability of nonlinear adversaries to recover the concept. |
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| Challenge: | Advances in automated event extraction yield massive data sets of “who did what to whom” micro-records that enable data-driven approaches to monitoring conflict. |
| Approach: | They propose a probabilistic generative model that assumes each observed event is associated with a latent intensity class. |
| Outcome: | The proposed model obtains comparatively good held-out predictive performance on a conflictual to cooperative scale. |
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| Challenge: | Shannon entropy is a quantity of interest for linguists studying the communicative capacity of human language. |
| Approach: | They propose to use entropy estimators to estimate linguistic effects from observed data . they propose to recommend better entropic estimators for future linguistic studies . |
| Outcome: | The proposed estimators are over-estimated due to poor entropy estimators, the authors argue . they recommend the same estimators be used in future linguistic studies. |
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| Challenge: | Neural sequence-to-sequence models with soft attention outperform monotonic models . current dominant method is the neural sequenceto-Sequency model with soft focus . |
| Approach: | They develop a hard attention sequence-to-sequence model that enforces strict monotonicity and learns alignment jointly. |
| Outcome: | The proposed model achieves state-of-the-art on grapheme-to-phoneme conversion and morphological inflection generation. |
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| Challenge: | Existing work on finding the one-best dependency tree has not extended this to finding the K-best tree. |
| Approach: | They propose to simplify the K-best spanning tree algorithm by decoding the K best dependency trees with a root constraint. |
| Outcome: | The proposed algorithm can be used to find the K-best dependency trees without root constraint. |
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| Challenge: | Several recent papers claim to have achieved human parity at sentence-level machine translation. |
| Approach: | They propose to use a dataset with rich discourse annotations to evaluate MT performance . they find that MT outputs differ fundamentally from human translations in terms of latent discourse structures. |
| Outcome: | The proposed dataset builds upon the large-scale parallel corpus BWB . it covers 15,095 entity mentions in both languages and compares them to human translations . |
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| Challenge: | a novel model for estimating the unigram distribution is proposed for a language . the model is based on the word type and word type distributions, but does not consider contextual information. |
| Approach: | They propose a neuralization of Goldwater's (2011) model for estimating the unigram distribution in a language. |
| Outcome: | The proposed model outperforms character-level models in estimating the unigram distribution in a language. |
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| Challenge: | Probabilistic context-free grammars are an important formalism in NLP . |
| Approach: | They propose to run a probabilistic context-free grammar in O(n3|N|3 + |N|4), where n is the input length and |N is the number of non-terminals in the grammar. |
| Outcome: | The proposed algorithm runs in O(n3|N|3 + |N|4), where n is the input length and |N | is the number of non-terminals in the grammar. |
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| Challenge: | a recent study suggests that mode-seeking decoding methods produce unnatural language . a higher probability text is perceived as more human-like, but this is not the case with stochastic decoding . |
| Approach: | They propose to explain why higher-probability text is perceived as more human-like . they argue that human-type language should contain an amount of information close to entropy . |
| Outcome: | The proposed model produces lower-probability text, which is perceived as more human-like . elucidation of this hypothesis supports the hypothesis . |
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| Challenge: | Empirical evidence on the prevalence and limits of embeddings has been based on either laboratory setups or corpus data of relatively limited size. |
| Approach: | They use large, dependency-parsed corpora to capture clausal embedding through dependency graphs and assess their distribution. |
| Outcome: | The results show that there is no evidence for hard constraints on embedding depth . they also show that sentences with many embeddable clauses do not display a bias towards less deep embedded sentences. |
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| Challenge: | Using a pretrained language model, we can train language models on increasingly large amounts of data. |
| Approach: | They propose a dependency parser that constructs dependency trees by tagging words with elements from a finite set of possible tags. |
| Outcome: | The proposed approach achieves state-of-the-art performance of 96.4 LAS and 97.4 UAS on the Penn Treebank test set. |
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| Challenge: | researchers train supervised models to extract linguistic structure from output of another model . supervised model can be used to perform tasks such as part-of-speech tags or dependency trees . |
| Approach: | They compare a structural probe to a more traditional parser with a lightweight parameterisation. |
| Outcome: | The structural probe outperforms a traditional parser on seven of nine languages . the researchers found that the model outperformed the parsers by 11.1 points . |
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| Challenge: | Lexical ambiguity makes it difficult to compute useful statistics of a corpus. |
| Approach: | They propose a neural network-based model that fits a prior distribution over feature bundles to a list of unigram type counts and partitions each count among different analyses of that unigrammer. |
| Outcome: | The proposed model is based on a list of unigram type counts and partitions each count among different analyses of that unigrammer. |
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| Challenge: | Existing methods for gender bias mitigation for word embeddings are based on pre-trained word embeds . however, the assumption that the bias subspace is linear is untested . |
| Approach: | They propose a method to isolate gender bias in word embeddings using pre-trained word embeds. |
| Outcome: | The proposed method eliminates gender bias in word embeddings but assumes bias subspace is linear . the proposed method has some drawbacks, but it is a good one for a non-linear analysis. |
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| Challenge: | a successful intervention should flip the correct with the wrong token, while remaining sparse. |
| Approach: | They propose to use activation scaling to flip the correct with the wrong token . they use gradient-based optimization to learn and evaluate a specific kind of efficient intervention . |
| Outcome: | The proposed method performs comparable with steering vectors but is much less minimal. |
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| Challenge: | Scholars of human development have long debated whether these phenomena are predetermined by innately encoded developmental changes in the maturing brain or natural consequences of increased experience. |
| Approach: | They use language models to test whether CP effects are peculiar to humans . they find that LMs do not show CP when L2 exposure is delayed . scholars have long debated whether innate maturation changes predetermine CP . |
| Outcome: | The proposed model does not show CP effects when the age of exposure of L2 is delayed. |
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| Challenge: | Syntactic control of generated text is crucial for many domain-specific applications of language models, where structural constraints, such as formality, grammatical correctness, or adherence to a given template, can significantly affect usability and readability. |
| Approach: | They propose to use posterior inference to enforce target constituency structure by sampling from a proposal distribution with a syntactic tagger to ensure that each generated token aligns with the desired syntakic structure. |
| Outcome: | The proposed method increases the F1 score from 12.31 (GPT2-large) and 35.33 (Llama3-8B) to about 93 in both cases without compromising the language model’s fluency. |
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| Challenge: | A grammatical gender system divides a lexicon into a small number of fixed categories with fixed usage across speakers. |
| Approach: | They propose to define gender systems extensionally to reduce comparisons to cluster evaluation by comparing pairwise overlaps between gender systems. |
| Outcome: | The proposed measures are based on a phylogenetic tree over extant Indo-European languages. |
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| Challenge: | Recent years have seen a paradigm shift in NLP towards using pretrained language models for a wide range of tasks. |
| Approach: | They propose to model structures as sequences of actions in autoregressive manner with PLMs . their approach allows in-structure dependencies to be learned without any loss . |
| Outcome: | The proposed approach achieves state-of-the-art on all structured prediction tasks. |
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| Challenge: | Existing studies show that training word embeddings in large corpora could lead to encoding societal biases present in these human-produced data. |
| Approach: | They conduct several intrinsic analyses to quantify, analyze and mitigate gender bias exhibited in ELMo’s contextualized word vectors. |
| Outcome: | The proposed method mitigates gender bias on WinoBias probing corpus and demonstrates that it can be implemented in other systems. |
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| Challenge: | surprisingly, beam search results on language generation tasks are low-quality . despite its high error rate, beam searches can be used to decode models with high probability . |
| Approach: | They frame beam search as the exact solution to a different decoding objective . they propose a set of decoding objectives that explicitly enforce this property . |
| Outcome: | The proposed method enforces uniform information density in text, a property motivated by cognitive science. |
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| Challenge: | a combinatorial model of human language often involves dynamic programming. |
| Approach: | They propose to search for a sequence of semantics-preserving transformations to improve the initial program's running time. |
| Outcome: | The proposed algorithm can find speed-ups in the initial program, and it can be used to improve it. |
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| Challenge: | Existing studies have investigated how often a model will rely on prior knowledge over conflicting contextual information in answering questions. |
| Approach: | They propose two mutual information-based metrics to measure a model’s dependency on a context and on its prior about an entity. |
| Outcome: | The proposed metrics show that language models can integrate prior knowledge and new information in a predictable way across different questions and contexts. |
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| Challenge: | a dependency tree has a root constraint, but only one edge may emanate from the root node. |
| Approach: | They propose an algorithm which enforces a root constraint without compromising the original runtime. |
| Outcome: | The proposed algorithm satisfies the constraint without compromising the original runtime. |
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| Challenge: | In some pathological situations, such a stochastic process may "leak" probability mass onto the set of infinite strings. |
| Approach: | They propose to view a language model as a discrete stochastic process X t : t = = t + . |
| Outcome: | The proposed conditions of tightness are generalized to language models and the literature. |
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| Challenge: | Understanding the expressive power of transformers has attracted attention . many studies analyze unique hard attention transformers, where attention selects a single position that maximizes the attention scores. |
| Approach: | They propose to use unique hard attention to select a single position that maximizes attention scores . they show that models with leftmost-hard attention are equivalent to soft attention . |
| Outcome: | The proposed models with leftmost-hard attention are equivalent to soft attention, suggesting they may better approximate real-world transformers than right-attention models. |
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| Challenge: | Pre-trained language models can be used to perform a wide array of NLP tasks, but their encoding is still a mystery. |
| Approach: | They propose a usage-based probing setup to find an encoding that the model actually uses, and propose 'a use-based approach' they propose to use a behavioral task to remove the linguistic property, and to identify which encodes are used to transfer information from a noun to its head verb. |
| Outcome: | The proposed encodings are based on a behavioral task which cannot be solved without the linguistic property. |
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| Challenge: | a new beam search approach allows for a diverse subset selection process . standard beam search does not encode interactions between candidates . |
| Approach: | They propose a beam search reformulation that casts subset selection as the subdeterminant optimization problem. |
| Outcome: | The proposed method offers competitive performance against other diverse set generation strategies while providing a more general approach to optimizing for diversity. |
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| Challenge: | Angluin (1987) introduced the active learning scheme L , where the learner interacts with an oracle by asking it queries. |
| Approach: | They propose a weighted variant of Angluin's (1987) L* algorithm for learning finite state automatas from black-box models. |
| Outcome: | The proposed algorithm learns aminimal automaton for the target language. |
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| Challenge: | Recent studies of the representational capacity of neural LMs have focused on their ability to recognize formal languages. |
| Approach: | They propose to connect recurrent neural networks (RNNs) as classifiers to finite-state automatas (FSAs) and a probabilistic FSA to characterize their representational capacity. |
| Outcome: | The proposed models can express arbitrary regular LMs with linearly bounded precision. |
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| Challenge: | Existing studies have demonstrated that NLP models possess the ability to generalize compositionally, but none have tested it. |
| Approach: | They propose to use a group-equivariant neural network to encode an inductive bias for SCAN to test for this ability. |
| Outcome: | The proposed architecture outperforms existing group-equivariant approaches on the SCAN task and shows that it can generalize compositionally. |
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| Challenge: | a recent study suggests that language models perform poorly across languages. |
| Approach: | They propose a model that fits a paired-sample multiplicative mixed-effects model to obtain language difficulty coefficients from at least-pairwise parallel corpora. |
| Outcome: | The proposed model is able to handle missing data and is aware of inter-sentence variation. |
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| Challenge: | Existing methods to detect cross-linguistic associations are not effective, but their effects are minor. |
| Approach: | They propose a method to measure cross-linguistic associations by controlling for the influence of language family and geographic proximity within a large concept-aligned, cross-lingual lexicon. |
| Outcome: | The proposed method shows that it is small, but it is unsurprisingly small (less than 0.5% on average). |
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| Challenge: | Weighted finite-state automata (WSFAs) are common formalisms in NLP. |
| Approach: | They propose an algorithm for semiring-weighted WFSAs with av-erage out symbol fractions . |
| Outcome: | The proposed algorithms are faster than the standard methods for weighted finite-state automata. |
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| Challenge: | Existing theories of communication cost are based on the length of an utterance, but they are not based upon the frequency of the utterant. |
| Approach: | They propose a method to minimize CCH's cost by comparing language lengths to surprisal's expectation and variance-to-mean ratios. |
| Outcome: | The proposed method does not minimize CCH’s cost, but rather a lower bound, which we term CCH-lower. |
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| Challenge: | Current legal outcome prediction models do not explain their reasoning in the real world, but human legal actors need to understand the model’s decisions. |
| Approach: | They propose a method for identifying the precedent employed by legal outcome prediction models and a taxonomy of legal precedent to compare human judges and neural models. |
| Outcome: | The proposed model learns to predict outcomes reasonably well, but its use of precedent is unlike that of human judges. |
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| Challenge: | a study of neural language models shows that syntactic probes do not properly isolate syntax. |
| Approach: | They show that syntactic probes do not properly isolate syntax . they train two probes trained on normal data and find they perform worse . |
| Outcome: | The proposed method outperforms the baseline models on the most popular models, but their lead is reduced by 53%. |
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| Challenge: | Existing measures of linguistic complexity are relatively coarse-see, for example, Moran and Blasi (2014) and 2 below for reviews. |
| Approach: | They propose to measure bits per phoneme using the negative log-probability of a word in a language model and a collection of 1016 basic concept words across 106 languages. |
| Outcome: | The proposed measure allows a cross-linguistic comparison of phonotactic complexity across languages. |
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| Challenge: | lexical meanings are mapped to wordforms by usage pressures and constraints on sequences of symbols. |
| Approach: | They propose a coding-theoretic view of the lexicon and a novel generative statistical model to quantify its compressibility under various constraints. |
| Outcome: | The proposed model shows that (compositional) morphology and graphotactics can account for most of the complexity of natural codes—as measured by code length. |
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| Challenge: | Gender stereotypes are manifest in most of the world's languages and are consequently propagated or amplified by NLP systems. |
| Approach: | They propose a method for converting between masculine-inflected and feminine-infflectes sentences in morphologically rich languages to reduce gender stereotyping by a factor of 2.5 without any sacrifice to grammaticality. |
| Outcome: | The proposed approach reduces gender stereotyping by 2.5 without any sacrifice to grammaticality. |
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| Challenge: | Uniform Information Density (UID) hypothesis posits that speakers tend to distribute information evenly across linguistic units to achieve efficient communication. |
| Approach: | They propose a functional pressure that speakers modulate information rate based on location within a hierarchically-structured model of discourse. |
| Outcome: | The proposed hypothesis posits that speakers tend to distribute information evenly across linguistic units to achieve efficient communication. |
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| Challenge: | Current approaches to bilingual lexicon induction (BLI) ignore inflectional morphology . current models degrade when translating less frequent inflected forms . |
| Approach: | They propose a morphologically aware probability model that models lexeme translation and inflectional morphology in a structured way. |
| Outcome: | The proposed model improves performance across 6 language pairs and in the weakly supervised setting. |
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| Challenge: | In many languages, nouns possess grammatical genders. |
| Approach: | They use large-scale corpora and tools from NLP and information theory to test whether there is a relationship between grammatical genders of inanimate nouns and adjectives used to describe them. |
| Outcome: | The results show that there is a statistically significant relationship between the grammatical genders of inanimate nouns and adjectives used to describe them in all six languages. |
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| Challenge: | a discrepancy in probabilistic language generators has puzzled the language generation community for years . |
| Approach: | They propose a method for local typical sampling to enforce a conditional entropy criterion for probabilistic models. |
| Outcome: | The proposed method can provide new insights into why high-probability texts can be dull or repetitive. |
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| Challenge: | Language models are increasingly being studied as models of human language learners. |
| Approach: | They propose a distributional approach to word learning that captures distributional knowledge and gradient preferences for the word’s appropriateness. |
| Outcome: | The proposed signatures capture knowledge of where the target word can and cannot occur as well as gradient preferences about the word’s appropriateness. |
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| Challenge: | Inductive biases are inherent in every machine learning system, argues a new study . m-local entropy measures how well symbols disambiguate the next symbol . |
| Approach: | They propose a framework that captures local uncertainty of a language by quantifying how effectively preceding symbols disambiguate the next symbol. |
| Outcome: | The proposed framework captures the local uncertainty of a language by quantifying how effectively symbols disambiguate the next symbol. |
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| Challenge: | Large-scale pretraining and task-specific fine-tuning are now the standard methodology for many tasks in computer vision and natural language processing. |
| Approach: | They propose to combine two types of vision and language BERTs to create a theoretical framework that can be unified under different theoretical frameworks. |
| Outcome: | The proposed models can be classified into single-stream or dual-stream encoders and are unified under a single theoretical framework. |
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| Challenge: | The uniform information density hypothesis posits a preference among language users for utterances structured such that information is distributed uniformly across a signal. |
| Approach: | They propose to test the hypothesis by using reading time and acceptability data to examine the effect of surprisal on language comprehension and acceptabilities. |
| Outcome: | The proposed hypothesis makes predictions about language comprehension and linguistic acceptability . |
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| Challenge: | a class of tree-adjoining languages can be characterized by various two-level formalisms controlled by semiring-weighted CFGs and PDAs. |
| Approach: | They propose semiring-weighted versions of controllable CFGs and PDAs . they also introduce a WPDA normal form that is analogous to Chomsky's normal form for CFG . |
| Outcome: | The proposed algorithms are more time-efficient than the previous ones for LIG, PAA, and EPDA. |
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| Challenge: | Existing prefix parsers are typically tied to particular parsing algorithms. |
| Approach: | They propose a prefix grammar transformation that reduces prefix parsing to ordinary parsers . they propose enabling prediction of the next token by computing the next-token weight vector . |
| Outcome: | The proposed method reduces prefix parsing to ordinary parsers without modification . the transformed grammar is only a small factor larger than the input . |
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| Challenge: | Recent research suggests that transformer-based language models fail to learn basic algorithmic patterns. |
| Approach: | They propose to augment transformer-based language models with a differentiable stack-based attention mechanism that adds a level of interpretability to the model. |
| Outcome: | The proposed model can model some, but not all, deterministic context-freelanguages. |
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| Challenge: | a recent study has investigated the nature of vowel inventories, i.e., which vowels a language contains . a probabilistic approach does not rule out linguistic systems completely, but it can position phenomena on a scale from very common to very improbable. |
| Approach: | They propose a generative probability model of vowel inventory typology based on acoustic information rather than discrete symbols from the international phonetic alphabet. |
| Outcome: | The proposed model uses acoustic information rather than discrete symbols from the phonetic alphabet. |
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| Challenge: | Existing studies show that global and local attention are expressively complementary. |
| Approach: | They propose to restrict global attention to a fixed-size window of preceding tokens . they also propose to add local attention to local-only transformers to increase model quality . |
| Outcome: | The proposed model outperforms the global–local transformers on formal language recognition and natural language modeling. |
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| Challenge: | morphological inflectors typically trained on fully supervised, type-level data, but how can we improve their performance? et al., 2016: a novel latent-variable model for semi-supervised learning of inflection generation. |
| Approach: | They propose a latent-variable model for semi-supervised learning of inflection generation . they use a wake-sleep algorithm to enable posterior inference over latent variables . |
| Outcome: | The proposed model improves on 23 languages and shows 10% accuracy improvement . the proposed model is based on the wake-sleep algorithm . |
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| Challenge: | idiosyncrasies of the Chinese classifier system have been studied, but little work has been done to quantify them with statistical methods. |
| Approach: | They propose an information-theoretic approach to measuring idiosyncrasies in Mandarin Chinese by calculating the mutual information between the distribution over classifiers and distributions over other linguistic quantities. |
| Outcome: | The proposed method reduces uncertainty in Mandarin Chinese classifiers by knowing semantic information about nouns that they modify. |
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| Challenge: | Neural networks are a pillar of modern NLP systems, but their inner workings are poorly understood. |
| Approach: | They propose a probe metric that reflects the trade-off between probe complexity and performance: the Pareto hypervolume. |
| Outcome: | The proposed probe metric conforms to accepted rankings among contextual representations, and is more complex than other probe tasks. |
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| Challenge: | Existing studies have sought to determine to what extent language models can serve as useful models of human cognition by aligning them to human psychometric data. |
| Approach: | They propose a method to fine-tune a language model to implicitly optimize parameters of a linear regressor that directly predicts humans’ reading times of in-context linguistic units. |
| Outcome: | The proposed technique improves language models’ psychometric predictive power but also its perplexity on held-out test data. |
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| Challenge: | a new perspective on how readers integrate context during reading time prediction is presented . a recent study shows that the proportion of variance in reading times explained by context is smaller when context is represented by the orthogonalized predictor. |
| Approach: | They propose a technique where they project surprisal onto the orthogonal complement of frequency. |
| Outcome: | The proposed method shows that the proportion of variance in reading times explained by context is smaller when context is represented by the orthogonalized predictor. |
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| Challenge: | Existing methods for controlling language generation are not able to produce fluent text . current methods require additional models or fine-tuning to ensure specific words are included . |
| Approach: | They propose a plug-and-play decoding method that allows for controlled language generation . they add a shift in the probability distribution over our vocabulary towards semantically similar words . |
| Outcome: | The proposed method outperforms competing methods in human evaluations and does not impact fluency. |
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| Challenge: | Language typically does not maintain a uniform information rate, but it fluctuates around a global average . a new study suggests periodicity may be a factor in information rate oscillations . |
| Approach: | They propose a hypothesis that language does not maintain a uniform information rate . they apply harmonic regression and introduce a new extension to detect periodicity . |
| Outcome: | The proposed method reveals that language oscillates at periodic intervals across frequencies . it also offers a framework for uncovering structural pressures at various levels of linguistic granularity. |
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| Challenge: | Existing work has tested transformers' ability to represent formal languages, but language models are not classifiers of strings but rather distributions over them. |
| Approach: | They relate transformers' ability to learn random n-gram language models to ngram language model (LM) they find add- smoothing outperforms transformers on the former, while transformers perform better on the latter . |
| Outcome: | The proposed models outperform classical methods designed to learn n-gram LMs, while transformers perform better on the latter. |
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| Challenge: | Currently, beam search is the default for decoding structured predictors . however, little work has been done to speed up beam search itself . |
| Approach: | They propose a beam search algorithm that prunes the scoring function to a monotonic sequence length, which allows for safe pruning of hypotheses that cannot be in the final set of hypothecies. |
| Outcome: | The proposed method can be implemented up to 10x faster in practice. |
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| Challenge: | We generalize the Bar-Hillel intersection construction so that the given WFSA may contain -arcs. |
| Approach: | They propose a construction that generalizes the Bar- Hillel in the case the desired automaton has -arcs and generalize the weighted extension so that the given WFSA may contain arcs. |
| Outcome: | The proposed construction can encode the structure of both the input automaton and grammar while retaining the asymptotic size of the original construction. |
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| Challenge: | Existing methods to evaluate test statistic are Monte Carlo approximations which use a summation over all 2 N possible swaps. |
| Approach: | They propose an exact algorithm for the paired-permutation test for a family of structured test statistics. |
| Outcome: | The proposed algorithm is 10x faster than the Monte Carlo approximation with 20000 samples on a common dataset. |
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| Challenge: | A longstanding debate in semiotics centers on the relationship between linguistic signs and their corresponding semantics: is there an arbitrary relationship between word forms and their meaning, or does some systematic phenomenon pervade? |
| Approach: | They propose to quantify the systematicity of the sign using mutual information and recurrent neural networks to examine 106 languages. |
| Outcome: | The proposed model reduces entropy in a word form conditioned on its semantic representation and recovers English examples of systematic affixes. |
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| Challenge: | Existing attempts to mitigate gender bias rely on operationalisation of gender bias as a projection over a linear subspace. |
| Approach: | They propose to operationalise gender bias as a linear subspace and augmented a corpus to remove bias by swapping all inherently-gendered words in the copy. |
| Outcome: | The proposed approach outperforms projection-based methods at the task of drawing non-biased gender analogies by an average of 19% across both corpora. |
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| Challenge: | Standard models that focus on fixation durations ignore spatial dynamics of reading . authors propose a model that captures how long fixations last, where they land and when . |
| Approach: | They propose a generative model that captures how long fixations last and where they land and when they occur. |
| Outcome: | The proposed model exhibits higher likelihood on held-out reading data than baselines. |
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| Challenge: | a new framework for structured prediction is developed for natural language processing . a systematic approach to structured prediction requires exhaustive pair-wise comparisons of tokens . |
| Approach: | They propose a method that models the relationship between pairs of tokens in a string . they use a parallel method that predicts real numbers for each token in . |
| Outcome: | The proposed method doubles the speed of graph-based dependency parsers and brings 10-times speed-up over graph-driven dependency parses. |
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| Challenge: | Existing methods for erasing human-interpretable concepts from neural representations that assume linearity are not fully understood. |
| Approach: | They define linear guardedness as the inability of an adversary to predict the concept directly from the representation . they show that a log-linear model can be constructed that indirectly recovers the concept . |
| Outcome: | The proposed model can be constructed that indirectly recovers the erased concept in some cases. |
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| Challenge: | lexical studies of word processing and lexicon access provide evidence of preferred nature of word-initial versus word-final segments . conjecture that languages have evolved to provide more information earlier in words is based on existing methods . |
| Approach: | They propose to use a new method to assess the informativeness of word-initial versus word-final segments. |
| Outcome: | The proposed measures avoid the confounds found in existing methods. |
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| Challenge: | Existing approaches to reduce constituency parsing to tagging are based on linearization, learning, and decoding . linearization of the derivation tree is the most critical factor in achieving accurate parsers as taggers . |
| Approach: | They propose a pipeline with three steps for reducing constituency parsing to tagging . they find that linearization and learning are critical factors for accurate parsers . |
| Outcome: | The proposed pipelines are linearized, learning, and decoded, and have three steps to achieve accurate parsing as taggers. |
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| Challenge: | Existing methods for probing are limited and lack understanding of their limitations and weaknesses. |
| Approach: | They propose a strategy for input-level intervention on naturalistic sentences . they use morpho-syntactic features of a sentence to intervene on the rest of the sentence . |
| Outcome: | The proposed approach allows for input-level intervention on naturalistic sentences while keeping the rest of the sentence unchanged. |
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| Challenge: | Pre-trained contextual representations have led to performance improvements on downstream tasks. |
| Approach: | They propose a Bayesian framework that quantifies the amount of inductive bias that the representations encode on a specific task. |
| Outcome: | The proposed framework alleviates many problems found in probing and can offer better inductive bias than BERT. |
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| Challenge: | Language models provide a naturalistic framework for studying artificial language learning . authors: typological universals and tendencies are thought to be caused by a learning bias . |
| Approach: | They propose to train LMs on highly naturalistic counterfactual versions of English and Japanese . they show that LM learn subtly implausible languages more slowly . |
| Outcome: | The proposed language models learn subtly implausible languages more slowly compared to human models . the findings suggest that LMs exhibit typologically aligned learning preferences . |
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| Challenge: | a recent study suggests that decoding strategies may be more important than the model architecture itself when generating text from probabilistic models. |
| Approach: | They propose to measure changes in attributes of generated text as a function of decoding strategy and task using human and automatic evaluation. |
| Outcome: | The proposed study shows that decoding strategies do not always transfer across tasks . authors show that the differences in attributes are not always consistent across tasks, they say . |
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| Challenge: | Legal outcome prediction is an increasingly popular task in AI. |
| Approach: | They propose to use the dynamics of a court process to develop two new models inspired by the dynamics. |
| Outcome: | The proposed model improves positive outcome prediction score to 77.15 F1 and doubles negative outcome prediction performance to 24.01 F1. |
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| Challenge: | False positive: a core NLP task of lemmatization seeks to map multiple forms of English verbs to a canonical one, known as the lemma. |
| Approach: | They propose a joint neural model for lemmatization and morphological tagging that achieves state-of-the-art results on 20 languages from the Universal Dependencies corpora. |
| Outcome: | The proposed model achieves state-of-the-art results on 20 languages from the Universal Dependencies corpora. |
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| Challenge: | Language models are used in computational psycholinguistics to test theories that relate the surprisal of a region of interest to its cognitive cost experienced by readers. |
| Approach: | They propose to marginalize token-level language models into character-level ones before they are used in psycholinguistic studies. |
| Outcome: | The proposed model over token strings is better than character-level model, the authors show . the proposed model marginalizes token-level models into character-based models before they are used in psycholinguistic studies. |
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| Challenge: | a recent study has compared real and counterfactual word orders, but one functional pressure has been overlooked . a study of 10 typologically diverse languages shows that real word orders have greater uniformity than reverse word orders . |
| Approach: | They propose to test whether a pressure for UID may have influenced word order patterns cross-linguistically. |
| Outcome: | The proposed model shows that real orders have greater uniformity than reverse orders among SVO languages. |
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| Challenge: | The Universal Morphology project is a collaborative effort to improve how NLP handles complex morphology across the world's languages. |
| Approach: | They propose to use a universal tagset to annotate morphological data using a schema that includes a lemma and a bundle of morphology features. |
| Outcome: | The project releases annotated morphological data using a universal tagset, the UniMorph schema. |
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| Challenge: | Recent work by Hewitt et al. (2020) provides an interpretation of the empirical success of recurrent neural networks (RNNs) as language models (LMs). |
| Approach: | They generalize their construction and show that RNNs can efficiently represent a larger class of LMs than previously claimed. |
| Outcome: | The results suggest that RNNs can represent a larger class of LMs than previously claimed . |
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| Challenge: | a recent study examines the morality of NLP models that can take in arbitrary text and output a moral judgment . a Delphi project is a popular system for moral prediction, but it has received criticism . |
| Approach: | They propose to critique NLP methods for automating ethical decision-making . they examine a nascent task of predicting moral and ethical decisions from text . |
| Outcome: | The proposed model is unsafe at any accuracy, the authors argue . they argue that the proposed model could be useful in NLP, but not in AI. |
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| Challenge: | Spanning trees are a fundamental model of dependency structure in natural language processing, syntactic dependency trees. |
| Approach: | They propose to use a spanning tree sampling algorithm to faithfully sample dependency trees from a graph subject to a root constraint. |
| Outcome: | The proposed sampling algorithm can sample K trees without replacement in O(K N3 + K2 N) time. |
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| Challenge: | Existing multilingual speech corpora have limited data in many languages . existing corpus is limited to a small number of languages with available data . |
| Approach: | They propose a large-scale phonetic typology corpus with phoneme-level labels and phoneme alignments in 690 readings spanning 635 languages. |
| Outcome: | The proposed corpus covers 635 languages and includes acoustic-phonetic measures of vowels and sibilants. |
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| Challenge: | a fair comparison of language models is tricky because of the size of the corpora and the variability of orthographic systems. |
| Approach: | They propose a framework for fair cross-linguistic comparison of language models . they show that in some languages, textual expression is harder to predict with n-gram models compared to LSTM models based on translated text . |
| Outcome: | The proposed framework is based on translated text and language models on 21 languages. |
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| Challenge: | Empirically, through aseries of experiments, we show that TPS captures a more nuanced notion of persuasiveness than previously proposed metrics. |
| Approach: | They introduce a targeted persuasion score to quantify how persuasive a given context is to an LM. |
| Outcome: | Empirically, the proposed model captures a more nuanced notion of persuasiveness than previously proposed metrics. |
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| Challenge: | Existing studies have focused on LMs as formal languages, but they do not consider language membership. |
| Approach: | They extend the Turing completeness result to the probabilistic case . they show that a rationally weighted RLM can simulate any deterministic Turing machine . |
| Outcome: | The proposed model can simulate any deterministic Turing machine with rationally weighted transitions . the proposed model is based on recurrent neural networks with a rational weighting over strings . |
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| Challenge: | empirical work often leaves the notion of a unit underspecified . empirical work has sought to characterize the processing difficulty comprehenders experience . |
| Approach: | They propose a framework for reasoning about surprisal over arbitrary unit inventories . they argue that surprises should be explicit and treat tokenization as implementation detail . |
| Outcome: | The proposed framework disentangles the models' definitions and the regions of interest and treats tokenization as an implementation detail rather than a scientific primitive. |
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| Challenge: | Existing methods for bilingual lexicon induction take advantage of word embeddings, but our model is not as efficient as previous work. |
| Approach: | They propose a discriminative latent-variable model for bilingual lexicon induction that combines the bipartite matching dictionary prior and an embedding-based approach. |
| Outcome: | The proposed model outperforms existing models on six language pairs and shows that it mitigates hubness problem. |
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| Challenge: | a generalization of classical information-theoretic measures of predictive uncertainty is proposed for online language processing . entropy and surprisal are two commonly deployed information- theoretic measure of predictive uncertainties in sentence processing based on the probability distribution of upcoming sequences of linguistic units . |
| Approach: | They propose a generalization of classical information-theoretic measures of predictive uncertainty in online language processing based on simulations of incremental linguistic contexts. |
| Outcome: | The proposed generalization of classical measures of predictive uncertainty in online language processing yields a positive effect on reading times and cloze completion probability. |
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| Challenge: | Existing research examines the origins of militarized conflict by examining bi-lateral relationships between entity pairs and multi-lateral relations among multiple entities. |
| Approach: | They propose to use Wikipedia to model dyadic and systemic causes to compare their correlations with conflict between two entities. |
| Outcome: | The proposed graphs show that Wikipedia articles of allies are semantically more similar than enemies. |
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| Challenge: | a relationship exists between the quality of a string and its probability, p(y), under a language model, and the quality and quality of the string. |
| Approach: | They examine the probability-quality relationship in language models aligned to human preferences through reinforcement learning through human feedback. |
| Outcome: | The proposed method improves the quality of text sampled from a language model by skewing the model towards high-probability strings. |
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| Challenge: | a generative model of languages based on principles-and-parameters posits that languages toggle on or off . linguistic typologists use a set of universal parameters to determine which languages toggle . we show that the correlation between parameters is significant, and that it is not enough to write down the set of parameters available to languages. |
| Approach: | They propose a generative model of language based on exponential-family matrix factorisation. |
| Outcome: | a linguistic model outperforms baseline models on predicting held-out features by exploiting similarities between languages and their features. |
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| Challenge: | Existing studies suggest partial redundancy between prosody and linguistic information. |
| Approach: | They use large language models to estimate how much information is redundant between prosody and the words themselves. |
| Outcome: | The proposed model can predict prosodic features across prosodic features, including intensity, duration, pauses, and pitch contours. |
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| Challenge: | Abstractive summarization models exhibit the tendency to hallucinate, i.e., output content not supported by the source document. |
| Approach: | They propose a decoding strategy that optimizes for pointwise mutual information of source and target tokens when models exhibit uncertainty. |
| Outcome: | The proposed method decreases the probability of hallucinated tokens while maintaining the Rouge and BERT-S scores of top-performing decoding strategies. |
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| Challenge: | a general framework for inference in spanning tree models is presented . a spanning-tree model is a combinatorial structure that is important for natural language processing . |
| Approach: | They propose a general framework for inference in spanning tree models . they exploit a connection between expectations and gradients, which allows efficient algorithms . |
| Outcome: | The proposed framework is up to 15 times faster than existing algorithms and reduces runtime complexity by a factor of the sentence length. |
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| Challenge: | phonological form and meaning of nouns can provide imperfect clues, but they can also be indicative of grammatical gender. |
| Approach: | They propose a method to measure how much information can be gleamed from knowing the form and/or meaning of nouns. |
| Outcome: | The proposed method provides additional quantitative support for a classic linguistic finding that form and meaning are relevant for the classification of nouns into declensions. |
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| Challenge: | Existing methods to improve language models' performance do not exploit this phenomenon . |
| Approach: | They propose to use contextual information to select and construct prompts that improve model performance. |
| Outcome: | The proposed methods show that the mutual information between a context and a question is an effective gauge for language model performance. |
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| Challenge: | a large body of work on probing has demonstrated that language model representations encode a wealth of linguistic information, but it remains unclear whether they also capture cognitive signals about human processing. |
| Approach: | They use regularized linear regression to compare language model representations against scalar predictors. |
| Outcome: | The representations from early layers outperform surprisal in predicting early-pass measures such as first fixation and gaze duration. |
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| Challenge: | a current language model is able to incorporate information from a user-input context when answering queries, but it is not equally sensitive to subtle changes to that context. |
| Approach: | They propose a metric to quantify the degree to which contexts can influence a model’s response to a query at a distributional level. |
| Outcome: | The proposed method is comparable to Monte Carlo's estimated susceptibility across a diverse set of query domains despite being 70 faster. |
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| Challenge: | Existing studies show that multilingual pre-trained models can learn to generalise across languages . however, it remains unclear how these models learn to learn multilingual representations . |
| Approach: | They propose a hypothesis that multilingual pre-trained models can derive language-universal abstractions about grammar by aligning morphosyntactic markers that fulfil a similar grammatical function across languages. |
| Outcome: | The proposed model can derive language-universal abstractions even without explicit supervision. |
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| Challenge: | Standard evaluation metrics, e.g., BLEU, TER and METEOR, focus on the quality of translations at the sentence level and do not consider discourse-level features. |
| Approach: | They propose to use a metric to take discourse coherence into consideration by categorizing discourse-related spans and calculating the similarity-based F1 measure of categorized spans. |
| Outcome: | The proposed metric possesses better selectivity and interpretability at the document-level, and is more sensitive to document- level nuances. |
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| Challenge: | a typical approach to natural language processing tasks involves selecting text spans and making decisions about them. |
| Approach: | They propose a grammar-based structured span selection model which learns to make use of partial span annotations. |
| Outcome: | The proposed model improves on two popular span prediction tasks. |
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| Challenge: | Neural sequence-to-sequence models are the predominant choice for language generation tasks. |
| Approach: | They find that on word-level tasks, the empty string is often the global optimum . they suggest that the poor calibration of many neural models may stem from characteristics of a specific subset of tasks rather than general ill-suitedness of such models for language generation. |
| Outcome: | The results suggest that the poor calibration of many neural models may stem from characteristics of a specific subset of tasks rather than general ill-suitedness of such models for language generation. |
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| Challenge: | Interventions targeting the representation space of language models (LMs) have emerged as an effective means to influence model behavior. |
| Approach: | They propose a method to convert representation counterfactuals into string counterf actuals and analyze the linguistic alterations corresponding to the intervention. |
| Outcome: | The proposed method analyzes linguistic alterations corresponding to a given representation space intervention and interprets features utilized to encode a specific concept. |
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| Challenge: | Recent work shows that a large proportion of the heads in a Transformer’s multi-head attention mechanism can be safely pruned away without significantly harming the performance of the model. |
| Approach: | They propose a method that prunes a Transformer's multi-head attention mechanism away without significantly harming its performance. |
| Outcome: | The proposed method improves on natural language inference and machine translation tasks while offering precise control of sparsity level. |
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| Challenge: | Throughout human evolution, countless languages have evolved, each with unique features. |
| Approach: | They analysed a corpus of 600 languages to find strong evidence for a surprisal–duration trade-off between languages and languages. |
| Outcome: | The proposed model shows that phones are produced faster in languages where they are less surprising and vice versa. |
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| Challenge: | Existing studies on gender bias in word embeddings focus on English . however, these studies cannot be extended to languages with morphological agreement on gender . |
| Approach: | They propose new metrics to evaluate gender bias in word embeddings of English and Spanish . they extend existing approaches to mitigate gender bias while preserving original embeddables . |
| Outcome: | The proposed methods reduce gender bias while preserving the original embeddings. |
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| Challenge: | a recent paper suggests that probing should be seen as approximating a mutual information. |
| Approach: | They propose a Bayesian mutual information framework that probes probing representations from the perspective of Bayes' agents. |
| Outcome: | The proposed framework allows for more intuitive results in scenarios with finite data. |
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| Challenge: | Compositionality is a hallmark of human language, but it is not yet fully understood . recombining known primitive concepts into larger novel combinations is elusive . |
| Approach: | They use finite-state transducers to make a dataset with controllable compositionality . they find that the models either learn the relations completely or not at all . |
| Outcome: | The proposed model learns the relation completely or not at all on large datasets. |
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| Challenge: | a nascent literature on probing language models has focused on studying linguistic phenomena. |
| Approach: | They propose a framework for evaluating the fit of language models to natural language tendencies. |
| Outcome: | The proposed framework evaluates language models to the tendencies of natural language . it shows that the models learn only a subset of the tendancies considered . |
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| Challenge: | Direct preference optimization (DPO) fine-tunes language models with human preferences . but not all preference pairs are equal; sometimes, the preferred response is only slightly better than the dispreferred one. |
| Approach: | They propose a generalization of direct preference optimization that does not treat every preference pair equally during fine-tuning. |
| Outcome: | The proposed algorithm outperforms DPO on tasks with limited preference pairs . it requires the difference between likelihood of preferred and dispreferred response to be greater than offset value . |
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| Challenge: | Existing methods for beam search are based on a deterministic approach, but the results are not as accurate as those used in SBS. |
| Approach: | They propose a method that turns beam search into a stochastic process by using conditional Poisson sampling design instead of taking the maximizing set at each iteration. |
| Outcome: | The proposed method produces lower variance and more efficient estimators than SBS, even showing improvements in high entropy settings. |
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| Challenge: | Existing work studies the transformer architecture in terms of language acceptance . n-gram LMs can represent any ngram lm, giving a concrete lower bound on their probabilistic representational capacity. |
| Approach: | They propose to use transformer LMs to represent n-gram LM, a class of language models . they show transformer lms can exactly represent any ngram lmm, giving them a lower bound . |
| Outcome: | The proposed model can represent any n-gram LM, giving a lower bound on their probabilistic representational capacity. |
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| Challenge: | Subword tokenization is a key part of most NLP pipelines, but little is known about why some combinations lead to improved downstream model performance. |
| Approach: | They propose that good tokenizers lead to efficient channel usage . they propose that an optimal encoding assigns extremely long codes to low-frequency subwords . |
| Outcome: | The proposed tokenizers have a very strong correlation with BLEU in machine translation . the proposed function can be used to improve model performance in the downstream task . |
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| Challenge: | a novel method for investigating inductive biases of language models using artificial languages is proposed . we show that modern neural architectures used for language modeling are intrinsically black boxes . |
| Approach: | They propose a method to investigate inductive biases of language models using artificial languages . they use languages to create parallel corpora across languages that differ only in word order . |
| Outcome: | The proposed method shows that language models can be used to model a wide variety of languages. |
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| Challenge: | Neural networks are the backbone of modern stateof-the-art natural language processing systems. |
| Approach: | They propose an information-theoretic operationalization of probing as estimating mutual information that contradicts received wisdom . they evaluate on a set of ten typologically diverse languages often underrepresented in NLP research—plus English—totalling eleven languages. |
| Outcome: | The proposed model outperforms existing models on ten typologically diverse languages and English on 11 languages. |
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| Challenge: | a paradigm discovery problem is a task of learning an inflectional morphological system from unannotated sentences. |
| Approach: | They formalize the paradigm discovery problem and develop evaluation metrics for judging systems . they use word embeddings and string similarity to cluster forms by cell and by paradigm . |
| Outcome: | The proposed system suggests clustering by cell across different inflection classes is the most pressing challenge for future work. |
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| Challenge: | a recent study examined how much information a model's representations contain . a new approach to probing is to look exactly like the component . |
| Approach: | They propose a new probing principle that aims to estimate how much information a model could extract from its representations. |
| Outcome: | The proposed probes extract syntactic information from the representations of a neural network . the proposed probe is based on the architectural bottleneck principle . |
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| Challenge: | The Universal Morphology project provides broad-coverage instantiated morphological inflection tables for hundreds of diverse languages. |
| Approach: | They propose a language-independent feature schema for rich morphological annotation and a type-level resource of annotated data in diverse languages realizing that schema. |
| Outcome: | The proposed schema has added 66 new languages, including 24 endangered languages. |
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| Challenge: | n-gram smoothing techniques were used to overcome overfitting problems in neural language models for decades. |
| Approach: | They propose to convert any n-gram smoothing technique into a regularizer compatible with neural language models. |
| Outcome: | The proposed regularizers outperform label smoothing on language modeling and machine translation. |
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| Challenge: | morphological inflection generation and historical text normalization tasks are character-level tasks that outperform recurrent models. |
| Approach: | They propose a technique to handle feature-guided character-level transduction that further improves performance. |
| Outcome: | The transformer outperforms recurrent models on morphological inflection and historical text normalization tasks. |
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| Challenge: | Existing dictionaries are limited in coverage and sentiment scales vary widely; some are discrete others continuous. |
| Approach: | They propose a Bayesian generative model that learns a composite sentiment dictionary as an interpolation between six existing dictionaries with different scales. |
| Outcome: | The proposed model learns a composite sentiment dictionary as an interpolation between six existing dictionaries with different scales. |
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| Challenge: | a new measure of irregularity is proposed for inflectional morphology of languages . the measure is based on the predictability of forms in a language . |
| Approach: | They propose a measure of irregularity based on the predictability of forms in a language. |
| Outcome: | The proposed measure is the first of its breadth and confirms longstanding proposals from the linguistics literature. |
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| Challenge: | Pre-trained large language models have exhibited an impressive ability to learn in context across various domains, e.g., code generation, education, medicine and even medicine. |
| Approach: | They taxonomize existing candidate theories into three competing hypotheses that explain LLMs’ ability to learn in context. |
| Outcome: | The proposed model can learn a task from in-context examples presented in a demonstration and generalize it to the prompt. |
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| Challenge: | Fig. 1 shows how left-corner transformations remove left recursion from context-free grammars . a common use case is to remove left-recursed grammars, which is necessary for top-down parsing . |
| Approach: | They generalize left-corner transformations to support semiring-weighted production rules . they also provide finer-grained control over which left corners may be moved . |
| Outcome: | The proposed transformation removes left recursion from context-free grammars . it also provides finer-grained control over which left corners may be moved . |
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| Challenge: | Existing research on probing for linguistic structure in word embeddings has focused on intrinsic probing, but what these representations encode about linguistic structures remains unclear. |
| Approach: | They propose a framework that allows us to determine whether linguistic information in word embeddings is dispersed or focal. |
| Outcome: | The proposed framework allows us to determine whether linguistic information in word embeddings is dispersed or focal. |
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| Challenge: | In common law, the outcome of a new case is determined mostly by precedent cases, rather than by existing statutes. |
| Approach: | They propose to model the argumentation of precedent cases and compare them to a case out-come classification task to determine how the precedent influences the outcome of a new case. |
| Outcome: | The proposed method compared arguments of two longstanding jurisprudential views on the European Court of Human Rights (ECtHR) and the precedent cases. |
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| Challenge: | a growing percentage of natural language processing tasks focus on the generation of text from probabilistic language models. |
| Approach: | They will provide a centralized discussion of critical considerations when choosing how to generate from a language model. |
| Outcome: | This tutorial will provide a centralized discussion of critical considerations when choosing how to generate from a language model. |
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| Challenge: | Existing models of crosslinguistic adjective ordering have relied on native speakers' intuitive judgment, not corpus data. |
| Approach: | They propose a latent-variable model that can order adjectives across 24 languages . they use tools and techniques to find universal, cross-linguistic, hierarchical ordering tendencies . |
| Outcome: | The proposed model can order adjectives across 24 languages even when languages are different . similar ordering preferences have been found to apply universally across languages . |
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| Challenge: | a number of natural questions have been asked about the inductive biases of neural networks on core NLP tasks. |
| Approach: | They construct an informative prior for held-out languages on a task of character-level, open-vocabulary language modelling. |
| Outcome: | The proposed model outperforms baseline models with an uninformative prior in both zero-shot and few-shot settings, showing that it is imbued with universal linguistic knowledge. |
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| Challenge: | Language models (LMs) are at the forefront of NLP research due to their versatility across diverse tasks. |
| Approach: | This tutorial will provide a framework for formal analysis of modern language models using tools from formal language theory. |
| Outcome: | This tutorial will provide a framework for formal analysis of modern language models using tools from formal language theory (FLT). |
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| Challenge: | Recent theories of language optimality have tried to justify its prevalence, arguing that homophony enables the reuse of efficient wordforms and is thus beneficial for languages. |
| Approach: | They propose a new information-theoretic quantification of a language’s homophony: the sample Rényi entropy. |
| Outcome: | The proposed method is more nuanced than either Piantadosi et al.'s or Trott and Bergen's results. |
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| Challenge: | Several feature-attribution methods for interpreting deep neural networks rely on computing the gradients of a model’s output with respect to its inputs, but they reveal little about the inner workings of the model itself. |
| Approach: | They propose a generalized backpropagation algorithm that generalizes the gradient computation of a model to efficiently compute other interpretable statistics about the gradient graph of neural networks. |
| Outcome: | The proposed generalized algorithm can be used to compute other interpretable statistics about the gradient graph of a neural network, such as the highest-weighted path and entropy. |
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| Challenge: | Weighted finite-state machines (WFSMs) have a storied role in NLP . e.g., conditional random fields for part-of-speech tagging are considered special cases of WFSM. |
| Approach: | They propose an algorithm for evaluating derivatives of all orders that is faster than prior algorithms . they also find that it is faster for computing second-order expectations . |
| Outcome: | The proposed algorithm is faster than prior algorithms and can compute second-order expectations. |
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| Challenge: | Character-level string-to-string transductions are an important component of NLP tasks . hard non-monotonic attention models have been used for sequence modeling tasks involving characters . |
| Approach: | They propose an exact algorithm for marginalizing over the exponential number of non-monotonic alignments between two strings. |
| Outcome: | The proposed algorithm outperforms soft attention and improves performance over stochastic approximation. |
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| Challenge: | Sparse attention has been claimed to increase model interpretability . however, the attention distribution is typically over representations internal to the model rather than the inputs themselves . |
| Approach: | They conduct experiments to understand how sparsity affects our ability to use attention as an explainability tool. |
| Outcome: | The proposed model does not map to a sparse set of influential inputs, but rather to fewer inputs. |
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| Challenge: | Currently, there are only 24 languages in the world that have not been annotated . transferring knowledge across domains is a common solution . |
| Approach: | They propose a Bayesian generative model for the space of neural parameters that factorizes into latent variables for each language and each task. |
| Outcome: | The proposed model can perform better than state-of-the-art methods with a typologically diverse sample of 33 languages from 4 continents and 11 families. |
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| Challenge: | In this paper, we isolate the task of predicting a fully inflected sentence from its partially lemmatized version. |
| Approach: | They propose a task that requires morphological features to be inferred from sentential context . they propose morphology-based models that explicitly reconstruct morphologic features before predicting inflected forms . |
| Outcome: | The proposed model is able to predict inflected sentences without relying on morphological annotations. |
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| Challenge: | Using Earley's context-free parsing algorithm, we show that the speed-ups are effective in practice. |
| Approach: | They propose a context-free parsing algorithm with various known and new speed-ups that improve Earley's (1970) O(N3|G||R|) They also propose 'a binarized version' that achieves runtime of O(M| |G| when the grammar is represented compactly as a single finite-state automaton M. |
| Outcome: | The proposed algorithm can be used to reduce the complexity of CKY on a binarized version of the grammar G. |
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| Challenge: | a recent study has focused on the ways in which language is gendered . positive adjectives used to describe women are more often related to their bodies . |
| Approach: | They propose a model that models adjective choice and its sentiment given the natural gender of a head noun. |
| Outcome: | The proposed model shows that positive adjectives used to describe women are more often related to their bodies than positive adjective words used to explain men. |
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| Challenge: | Existing theoretical treatments have shed light on some aspects of CoT, but we are still far from a concrete understanding of the concept. |
| Approach: | They propose to formalize CoT reasoning in a probabilistic setting to bridge this gap . they show that LMs can represent the same family of distributions over strings as probabilistic Turing machines. |
| Outcome: | The proposed model can represent the same family of distributions over strings as Turing machines. |
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| Challenge: | Pre-trained language models have increased the performance of data-driven natural language processing (NLP) models on a wide variety of tasks. |
| Approach: | They propose a model-free approach to probing via prompting which formulates probing as a prompting task and combine pruning to analyze where the model stores the linguistic information in its architecture. |
| Outcome: | The proposed approach extracts information from pre-trained models while learning much less on its own. |
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| Challenge: | Explicit modeling of morphology has demonstrable benefits for language modeling, speech recognition, word embedding and keyword search. |
| Approach: | They propose a language-independent feature schema for rich morphological annotation and a type-level resource for annotated data in diverse languages. |
| Outcome: | The proposed schema has been improved to make it more complete and correct, and adds 66 new languages and parts of speech for 12 languages. |
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| Challenge: | Existing dynamic programming algorithms for PDAs often resort to a PDA-to-CFG conversion. |
| Approach: | They propose to use a pushdown automaton to reduce the space requirements by a factor of |Gamma| or the runtime by reducing the number of states. |
| Outcome: | The proposed algorithms reduce the space requirements by a factor of |Gamma| or reduce the runtime by fewer states. |
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| Challenge: | Probing is a method of investigating the encoding of knowledge in contextual representations. |
| Approach: | They propose to kernelize a metric and develop a non-linear variant with an identical number of parameters by using a kernel-based probe. |
| Outcome: | The proposed probe learns only linear transformations and achieves statistically significant performance improvement over baseline in all languages. |
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| Challenge: | Human translators have to translate rare inflections due to Zipfian distribution of words in a language. |
| Approach: | They introduce 40 morphologically complete dictionaries in 10 languages and evaluate three of the best performing models on the task of translation of less frequent morphology. |
| Outcome: | The proposed models perform better on infrequent morphological inflections and add a simple constraint at training time. |
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| Challenge: | Prior work has explored regularizing the output distributions of probabilistic models to alleviate overfitting. |
| Approach: | They propose a family of entropy regularizers that have a connection to regularization . they find that label smoothing provably does not allow for sparsity in an output distribution . |
| Outcome: | The proposed method improves the relationship between model entropy and performance on language generation tasks. |
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| Challenge: | Using sampling adapters can improve the quality of the generated text. |
| Approach: | They propose a framework for understanding sampling adapters and propose 'sampling adapters' they argue that the shift enforced by them can be viewed as a trade-off between precision and recall . |
| Outcome: | The proposed framework can be used to improve the quality of language models by modifying their distributions to improve their precision and recall. |
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| Challenge: | a uniform information density hypothesis is used to explain certain linguistic phenomena . a regularizer that encodes the UID hypothesis can be used for language training . |
| Approach: | They propose to augment the canonical MLE objective with a regularizer that encodes UID . they find that regularization consistently improves perplexity in language models . |
| Outcome: | The proposed hypothesis can be operationalized as an inductive bias for language modeling. |
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| Challenge: | Lexical ambiguity is widespread in language, allowing for the reuse of economical word forms and thus making language more efficient. |
| Approach: | They propose two ways to estimate lexical ambiguity as the entropy of meanings a word can take . they validate this hypothesis by using WordNet and BERT . |
| Outcome: | The proposed method shows that on six high-resource languages, there are significant correlations between the estimate and the number of synonyms a word has in WordNet. |
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| Challenge: | Existing studies have focused on the expressive power of recurrent neural network LMs to recognize unweighted formal languages. |
| Approach: | They propose to model a strict subset of probabilistic finite-state automata with RNNs . they show that an RNN requires left(N ||right) neurons to represent an LM . |
| Outcome: | The proposed language models can represent a strict subset of probabilistic distributions expressed by finite-state models. |
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| Challenge: | a new model of sentiment lexica is being developed to combine disparate scales into a common representation. |
| Approach: | They propose a model that unifies disparate scales into a common latent representation . they evaluate a text classification task using nine English-Language sentiment datasets . |
| Outcome: | The proposed model outperforms six individual sentiment lexica and a simple combination thereof. |
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| Challenge: | a lack of studies targeting naturalistic sentence-final reading behavior is likely to explain the lack of data on reading time (RT) data is omitted due to the confounding factors introduced by so-called "wrap-up effects" |
| Approach: | They propose to look for a link between “wrap-up effects” and information theoretic quantities such as word and context information content. |
| Outcome: | The proposed model omits data on words at the end of sentences or clauses to control for the confounding factors introduced by wrap-up effects. |
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| Challenge: | a large number of languages employ grammatical gender on the lexeme, but is it truly arbitrary? a recent study shows that the relationship between grammamatical gender and lexical semantics is opaque. |
| Approach: | They propose a method to correlating inanimate nouns' gender with lexical semantics . they find that the gender systems of 18 languages exhibit a significant correlation with a definition . |
| Outcome: | a new study shows that the gender assignments of 18 languages are arbitrary . the authors show that the correlation between gender and semantics is significant . |
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| Challenge: | Current state-of-the-art MT systems are based on neural networks, but it is unclear whether all translation directions are equally easy (or hard) to model for NMT. |
| Approach: | They propose an asymmetric information-theoretic metric of machine translation difficulty that exploits the probabilistic nature of most neural machine translation models. |
| Outcome: | The proposed metric allows us to better evaluate the difficulty of translating text into the target language while controlling for the difficulty independent of the translation task. |