Social changes can often bring about language changes.

The study of meaning in language is known as semantics.

Chomsky defines “competence” as the ideal user’s k（）of the rules of his language.

The distinction between competence and performance was proposed by F. de Saussure.

Semantics

P （）refers to the realization of langue in actual use.

A scientific study of language is based on what the linguist thinks.

D（）is one of the design features of human language which refers to the phenomenon that language consists of two levels: a lower level of meaningless individual sounds and a higher level of meaningful units.

Morphology studies how words can be formed to produce meaningful sentences.

Linguistics is generally defined as the s（）study of language.