2012/06/11 by Gerhard Jäger, James Rogers · 1 citation
Computer Science · Psychology · #semigroups and automata theory #Language Development and Disorders #Natural Language Processing Techniques
paper · pdf · doi:10.1098/rstb.2012.0077
openalex publication_date 2012/06/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/15
The first part of this article gives a brief overview of the four levels of the Chomsky hierarchy, with a special emphasis on context-free and regular languages. It then recapitulates the arguments why neither regular nor context-free grammar is sufficiently expressive to capture all phenomena in the natural language syntax. In the second part, two refinements of the Chomsky hierarchy are reviewed, which are both relevant to the extant research in cognitive science: the mildly context-sensitive languages (which are located between context-free and context-sensitive languages), and the sub-regular hierarchy (which distinguishes several levels of complexity within the class of regular languages).