Syntax

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.

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

Language

Sociolinguistics is the study of language in relation to society.

In the study of linguistics, hypotheses formed should be based on language facts and checked against the observed facts.

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.

Phonetics is different from phonology in that the latter studies the combinations of the sounds to convey meaning in communication.

Language is p（）in that it makes possible the construction and interpretation of new signals by its users. In other words, they can produce and understand an infinitely large number of sentences which they have never heard before.