مقایسهٔ روش‌ها

	گرامر ساختار عبارت مبتنی بر سر (HPSG)	Optimality Theory
حوزه	زبان‌شناسی	زبان‌شناسی
خانواده	Process / pipeline	Process / pipeline
سال پیدایش	1987	1993
پدیدآور	Carl Pollard and Ivan Sag	Alan Prince and Paul Smolensky
نوع	Empirical process pipeline	Empirical process pipeline
منبع بنیادین	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.
نام‌های دیگر	HPSG Grammar, Constraint-Based Syntax	OT, Constraint-Based Phonology
مرتبط	2	1
خلاصه	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.