Linguists traditionally analyse human language by observing an interplay between sound and meaning. Phonetics is the study of speech and non-speech sounds, and delves into their acoustic and articulatory properties. The study of language meaning, on the other hand, deals with how languages encode relations between entities, properties, and other aspects of the world to convey, process, and assign meaning, as well as manage and resolve ambiguity. While the study of semantics typically concerns itself with truth conditions, pragmatics deals with how situational context influences the production of meaning.
The study of parole (which manifests through cultural discourses and dialects) is the domain of sociolinguistics, the sub-discipline that comprises the study of a complex system of linguistic facets within a certain speech community (governed by its own set of grammatical rules and laws). Discourse analysis further examines the structure of texts and conversations emerging out of a speech community's usage of language. This is done through the collection of linguistic data, or through the formal discipline of corpus linguistics, which takes naturally occurring texts and studies the variation of grammatical and other features based on such corpora (or corpus data).
Language documentation combines anthropological inquiry (into the history and culture of language) with linguistic inquiry, in order to describe languages and their grammars. Lexicography involves the documentation of words that form a vocabulary. Such a documentation of a linguistic vocabulary from a particular language is usually compiled in a dictionary. Computational linguistics is concerned with the statistical or rule-based modeling of natural language from a computational perspective. Specific knowledge of language is applied by speakers during the act of translation and interpretation, as well as in language education the teaching of a second or foreign language. Policy makers work with governments to implement new plans in education and teaching which are based on linguistic research.
Discourse is language as social practice (Baynham, 1995) and is a multilayered concept. As a social practice, discourse embodies different ideologies through written and spoken texts. Discourse analysis can examine or expose these ideologies. Discourse influences genre, which is chosen in response to different situations and finally, at micro level, discourse influences language as text (spoken or written) at the phonological or lexico-grammatical level. Grammar and discourse are linked as parts of a system. A particular discourse becomes a language variety when it is used in this way for a particular purpose, and is referred to as a register. There may be certain lexical additions (new words) that are brought into play because of the expertise of the community of people within a certain domain of specialization. Registers and discourses therefore differentiate themselves through the use of vocabulary, and at times through the use of style too. People in the medical fraternity, for example, may use some medical terminology in their communication that is specialized to the field of medicine. This is often referred to as being part of the "medical discourse", and so on.