What Languages are Easy to Language-Model? A Perspective from Learning Probabilistic Regular Languages

Fuente: arXiv
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Main Authors: Borenstein, Nadav, Svete, Anej, Chan, Robin, Valvoda, Josef, Nowak, Franz, Augenstein, Isabelle, Chodroff, Eleanor, Cotterell, Ryan
Format: Preprint
Published: 2024
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author Borenstein, Nadav
Svete, Anej
Chan, Robin
Valvoda, Josef
Nowak, Franz
Augenstein, Isabelle
Chodroff, Eleanor
Cotterell, Ryan
author_facet Borenstein, Nadav
Svete, Anej
Chan, Robin
Valvoda, Josef
Nowak, Franz
Augenstein, Isabelle
Chodroff, Eleanor
Cotterell, Ryan
contents What can large language models learn? By definition, language models (LM) are distributions over strings. Therefore, an intuitive way of addressing the above question is to formalize it as a matter of learnability of classes of distributions over strings. While prior work in this direction focused on assessing the theoretical limits, in contrast, we seek to understand the empirical learnability. Unlike prior empirical work, we evaluate neural LMs on their home turf-learning probabilistic languages-rather than as classifiers of formal languages. In particular, we investigate the learnability of regular LMs (RLMs) by RNN and Transformer LMs. We empirically test the learnability of RLMs as a function of various complexity parameters of the RLM and the hidden state size of the neural LM. We find that the RLM rank, which corresponds to the size of linear space spanned by the logits of its conditional distributions, and the expected length of sampled strings are strong and significant predictors of learnability for both RNNs and Transformers. Several other predictors also reach significance, but with differing patterns between RNNs and Transformers.
format Preprint
id arxiv_https___arxiv_org_abs_2406_04289
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle What Languages are Easy to Language-Model? A Perspective from Learning Probabilistic Regular Languages
Borenstein, Nadav
Svete, Anej
Chan, Robin
Valvoda, Josef
Nowak, Franz
Augenstein, Isabelle
Chodroff, Eleanor
Cotterell, Ryan
Computation and Language
What can large language models learn? By definition, language models (LM) are distributions over strings. Therefore, an intuitive way of addressing the above question is to formalize it as a matter of learnability of classes of distributions over strings. While prior work in this direction focused on assessing the theoretical limits, in contrast, we seek to understand the empirical learnability. Unlike prior empirical work, we evaluate neural LMs on their home turf-learning probabilistic languages-rather than as classifiers of formal languages. In particular, we investigate the learnability of regular LMs (RLMs) by RNN and Transformer LMs. We empirically test the learnability of RLMs as a function of various complexity parameters of the RLM and the hidden state size of the neural LM. We find that the RLM rank, which corresponds to the size of linear space spanned by the logits of its conditional distributions, and the expected length of sampled strings are strong and significant predictors of learnability for both RNNs and Transformers. Several other predictors also reach significance, but with differing patterns between RNNs and Transformers.
title What Languages are Easy to Language-Model? A Perspective from Learning Probabilistic Regular Languages
topic Computation and Language
url https://arxiv.org/abs/2406.04289