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.

General linguistics, which relates itself to the research of other areas, studies the basic concepts, theories, descriptions, models and methods applicable in any linguistic study.

Morphology

Modern linguistics regards the written language as primary, not the written language.

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

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

Social changes can often bring about language changes.

Both semantics and pragmatics study meanings.

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.

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