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

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

The study of meaning in language is known as semantics.

Pragmatics

Language

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.

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

Linguistics

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.