constraint (n.)

A term used in LINGUISTICS, and especially in GENERATIVE GRAMMAR, to refer to a CONDITION which restricts the application of a RULE, to ensure that the sentences generated are WELL FORMED. For example, in generative PHONOLOGY, a distinction can be made between ‘simultaneous’ and ‘sequential’ constraints: the former states the restrictions on the simultaneous occurrence of FEATURES, e.g. a SEGMENT cannot be at once [+high] and [+low]; the latter states the restrictions on sequences of features, e.g. whether a language permits CONSONANT CLUSTERS. In generative SYNTAX there are also several constraints which have to be imposed in order to prevent the DERIVATION of ILL-FORMED PHRASE-MARKERS, e.g. constraints on the ORDERING of rules. For example, ‘surface structure’ constraints (FILTERS, or ‘OUTPUT conditions’) refer to conditions where a characteristic of SURFACE STRUCTURE decides which phrase-markers are well formed; e.g. no phrase-marker containing an internal boundary symbol can qualify as a well-formed surface structure. Other examples include ISLAND constraints and the CO-ORDINATE structure constraint.

Later generative studies aimed to find constraints which apply to large classes of derivations (i.e. the constraints have a greater EXPLANATORY power) – a trend which contrasts with the local application of the constraints proposed in the 1960s. ‘Constraints’, in this work, are distinguished from ‘filters’: the former are conditions affecting two successive phrase-markers in a derivation: the latter are conditions on a single level of structure, which serves as the output of a given set of rules.

The notion of constraints takes a different direction in OPTIMALITY THEORY, where it is the principal EXPLANATORY device (abbreviated as CON). Here, constraints are ways of characterizing language UNIVERSALS. Each language has its own RANKING of constraints (e.g. which determine MORPHEME position or SYLLABLE STRUCTURE), and differences between these rankings result in the variations observed between languages. Constraints are found only in the constraint hierarchy for a language, i.e. the language’s particular ranking of the universal set of constraints; there are no separate constraints operating on INPUTS or OUTPUTS, and no RULES to be constrained. The approach also uses the notion of constraint satisfaction, representing the extent to which a constraint can be violated in grammatical forms. All constraints are violable. The output forms are the OPTIMAL ones (i.e. with the minimum number of constraint VIOLATIONS), selected by the EVALUATOR component of the theory. The term is also used more generally in generative linguistics with reference to theory construction. A linguistic theory needs to be constrained, in order to restrict the class of potential grammars. In this sense, the main aim of linguistics is said to be the provision of an explanatorily ADEQUATE theory which is maximally constrained.

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اخبار العتبة العباسية المقدسة

قسم صناعة الشبابيك يشرع بإدامة شباكين قديمين لمرقد الإمامين العسكريين (عليهما السلام)

فرقة العباس (عليه السلام) تختتم خدماتها المقدمة للزائرين في سامراء

موكب العتبتين المقدستين يحيي ذكرى استشهاد الإمام الهادي (عليه السلام) في سامراء

العتبة العسكرية المقدسة تكرّم وفد العتبة العباسية المقدسة لمشاركته في تقديم الخدمات للزائرين

المزيد

الآخبار الصحية

كنز غذائي على طبقك.. ماذا تفعل السبانخ بجسمك؟

ما لا يتوقعه أحد.. "سر غذائي" في الجبن الدسم

لتحسين الهضم والنوم.. هذا أفضل وقت لتناول العشاء

10 طرق بسيطة وغير مألوفة لحرق المزيد من السعرات يوميا

المزيد

الآخبار التكنلوجية

سابقة بعالم الطيران.. طائرة تقرر الهبوط بنفسها بعد ظرف طارئ

"الإنفلونزا الخارقة" تكتسح دول العالم.. وتثير قلقا كبيرا

مرحلة ما قبل الأعراض.. دواء جديد يستهدف "شرارة" الزهايمر

إزالة ثاني أكسيد الكربون من الغلاف الجوي.. ما دور المحيطات والبحار؟

المزيد

مواضيع ذات صلة

Zero-anaphora (“pro-drop”)

Annotated Phrase Structure trees

Word-level (lexical) categories

Syntax and speech

Word Order- Classifiers and phrasal dependents in DP

Word order- Suffixal Pl and Art

Syntax Word order and restrictive vs. nonrestrictive modification

Syntax

Language Mixture—Grammar

Change in grammar and pronunciation

Word order

Grammaticalization.