Linguistics 

is the scientific study of language. Human language, understood as a systematic use of speech sounds, signs, and written symbols for communication among people, is a very complicated system, which can be analysed on different levels and from various points of view.

Language is defined as the method of human communication, either spoken or written. Consisting of the use of words in a structured and conventional way.

Principles of Modern Linguistics:

Structuralism: is a term used in linguistics referring to a theoretical approach to the analysis of language that describes linguistic items in 8 terms of structures. 

Linguistics is descriptive, not prescriptive

 It means that linguists describe the rules and facts of language exactly as they find them without making judgements. They do not try to impose norms of correctness and do not try to change the actual usage of the language of the native speakers. 

Synchronic and diachronic description of language

 Two basic principles can be applied to the study of language: synchronic and diachronic. Diachronic linguistics is the study of languages from the viewpoint of their historical development. Synchronic linguistics studies languages at a single point of time. 

Paradigmatic and syntagmatic relations of linguistic units

 A linguistic unit enters into relations of two different kinds which identify it in the language system. It enters into paradigmatic relations with all the other elements of the same level which can also be used in the same context. For example, in the phrase a…of milk; the missing element could be glass, jar, mug, bottle (all these concrete countable nouns stand in paradigmatic relationship). A linguistic unit enters into syntagmatic relations with the other elements of the same level with which it occurs and which make its context. Syntagmatic relations for the phrase a glass of milk would be between glass and a, of, and milk.