Linguistics is the study of language as a phenomenon, including its grammar, social aspects, and psychological aspects. It includes the formal study of linguistics, sociolinguistics involving social aspects, psycholinguistics concerning psychological aspects, and applied linguistics dealing with practical uses of language knowledge.

2.  Is the study of language.
Language as a
phenomenon.
Study: grammar, social and
psychological aspects of
language.

3. Formal linguistics.
Sociolinguistics.
Psycholinguistics.
Applied linguistics.