手法を比較

	HPSG	最適性理論
分野	言語学	言語学
系統	Process / pipeline	Process / pipeline
提唱年	1987	1993
提唱者	Carl Pollard and Ivan Sag	Alan Prince and Paul Smolensky
種類	Empirical process pipeline	Empirical process pipeline
原典	Pollard, C., & Sag, I. A. (1994). Head-Driven Phrase Structure Grammar. Chicago: University of Chicago Press.	Prince, A., & Smolensky, P. (1993). Optimality Theory: Constraint Interaction in Generative Grammar. Blackwell Publishers.
別名	HPSG Grammar, Constraint-Based Syntax	OT, Constraint-Based Phonology
関連	2	1
概要	Head-Driven Phrase Structure Grammar (HPSG) is a constraint-based grammatical framework developed by Carl Pollard and Ivan Sag in 1987. HPSG represents linguistic information (phonological, syntactic, semantic) in typed feature structures and derives well-formed expressions through constraints on these structures. Unlike movement-based theories, HPSG models word order and long-distance dependencies through feature sharing and principles of grammar. It has been extensively applied to modeling diverse language phenomena and remains influential in computational linguistics.	Optimality Theory (OT) is a constraint-based framework for modeling phonology and syntax, developed by Alan Prince and Paul Smolensky in 1993. The core idea is that languages produce the optimal output that best satisfies a ranked hierarchy of universal constraints. Rather than listing rules, OT explains linguistic phenomena as solutions to conflicting pressures—sounds and structures emerge as the least bad compromise among competing demands. This framework has revolutionized phonological theory and is widely applied to morphophonology, segmental and suprasegmental analysis, and cross-linguistic variation.