|Principles and Parameters|
| Definition -
A two-part framework within generative linguistics in which a language's syntax is described according to:
(1) non-variable principles (i.e. rules that all languages must obey) and
(2) variable parameters that for particular languages are either turned on or off.
(1) That sentences must always have subjects, even if the subject is not overtly pronounced is a principle, and
(2) whether a language is head-initial is a parameter that is either on or off for particular languages.
Etymology - This framework was formulated by Noam Chomsky and Howard Lasnik.