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.

Language

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

Pragmatics is different from semantics in that pragmatics studies meaning not in isolation, but in context.

General linguistics is generally the study of language as a whole.

The discipline that studies the rules governing the formation of words into permissible sentences in languages is called s（）

Linguistics

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.

Morphology

A diachronic study of language is the description of language at some point in time.