How (Non-)Optimal is the Lexicon?

Tiago Pimentel, Irene Nikkarinen, Kyle Mahowald, Ryan Cotterell, Damián Blasi


Abstract
The mapping of lexical meanings to wordforms is a major feature of natural languages. While usage pressures might assign short words to frequent meanings (Zipf’s law of abbreviation), the need for a productive and open-ended vocabulary, local constraints on sequences of symbols, and various other factors all shape the lexicons of the world’s languages. Despite their importance in shaping lexical structure, the relative contributions of these factors have not been fully quantified. Taking a coding-theoretic view of the lexicon and making use of a novel generative statistical model, we define upper bounds for the compressibility of the lexicon under various constraints. Examining corpora from 7 typologically diverse languages, we use those upper bounds to quantify the lexicon’s optimality and to explore the relative costs of major constraints on natural codes. We find that (compositional) morphology and graphotactics can sufficiently account for most of the complexity of natural codes—as measured by code length.
Anthology ID:
2021.naacl-main.350
Volume:
Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies
Month:
June
Year:
2021
Address:
Online
Editors:
Kristina Toutanova, Anna Rumshisky, Luke Zettlemoyer, Dilek Hakkani-Tur, Iz Beltagy, Steven Bethard, Ryan Cotterell, Tanmoy Chakraborty, Yichao Zhou
Venue:
NAACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
4426–4438
Language:
URL:
https://aclanthology.org/2021.naacl-main.350
DOI:
10.18653/v1/2021.naacl-main.350
Bibkey:
Cite (ACL):
Tiago Pimentel, Irene Nikkarinen, Kyle Mahowald, Ryan Cotterell, and Damián Blasi. 2021. How (Non-)Optimal is the Lexicon?. In Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, pages 4426–4438, Online. Association for Computational Linguistics.
Cite (Informal):
How (Non-)Optimal is the Lexicon? (Pimentel et al., NAACL 2021)
Copy Citation:
PDF:
https://aclanthology.org/2021.naacl-main.350.pdf
Video:
 https://aclanthology.org/2021.naacl-main.350.mp4