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

Phonetics

Both semantics and pragmatics study meanings.

Semantics

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.

The study of the ways in which morphemes can be combined to form words is called morphology.

Findings in linguistic studies can often be applied to the settlement of some practical problems. The study of such applications is generally known as a（）linguistics.

Social changes can often bring about language changes.

Langue refers to the a（）linguistic system shared by all the members of a speech community while the parole is the concrete use of the conventions and application of the rules.

Language is a system of a（）vocal symbols used for human communication.