¶ … appended meaning according to the Routledge Dictionary of Language and Linguistics. Sociolinguistics

Scientific discipline developed from the cooperation of linguistics and sociology that investigates the social meaning of the language system and of language use, and the common set of conditions of linguistic and social structure. Several areas of sociolinguistic investigation are differentiated.

(a) A primarily sociologically oriented approach concerned predominantly with the norms of language use. (When and for what purpose does somebody speak what kind of language or what variety with whom?) Here language use and language attitudes as well as larger and smaller social networks are in the foreground. These facets are studied mainly by using quantitative methods; connections between socioeconomics, history, culture, ethnic differentiation, social class structure, and language varieties are included in the investigation (diglossia, code theory).

(b) A primarily linguistically oriented approach that presumes linguistic systems to be in principle heterogeneous, though structured, when viewed within sociological parameters. For an appropriate description of linguistic variation, a new type of rule -- differentiated from rules found in generative grammar -is proposed, the so-called 'variable rule,' which expresses and establishes the probability that a particular linguistic form will result from the influence of different linguistic and extralinguistic variables, e.g. social class, age, etc. (variational linguistics). The results of this sociolinguistic approach have particularly important implications for the theory of language change: in a series of empirical investigations the relevance of social conditions to the processes of language change was demonstrated and proved, such that synchronically present variational structures can be seen as a 'snap shot' of diachronic changes.

(c) An ethnomethodologically oriented approach with linguistic...

Here a formal distinction must be drawn between conversation analysis, which deals with the structure of conversations, and ethnographic conversation analysis (ethnography of speaking), which investigates interactive processes in the production of meaning and understanding.
Language

Vehicle for the expression or exchanging of thoughts, concepts, knowledge, and information as well as the fixing and transmission of experience and knowledge. It is based on cognitive processes, subject to societal factors and subject to historical change and development. In this definition, language refers to a specific form of expression that is restricted to humans, and differs from all other possible languages, such as animal communication and artificial languages through creativity, the ability to make conceptional abstractions, and the possibility of metalinguistic reflection.

Varieties

Generic term for a particular coherent form of language in which specific extralinguistic criteria can be used to define it as a variety. For example, a geographically defined variety is known as a dialect, a variety with a social basis as a sociolect, a functional variety as jargon or a sublanguage, a situative variety as a register.

Dialects

A linguistic system (in the sense of langue) that:

(a) shows a high degree of similarity to other systems so that at least partial mutual intelligibility is possible;

(b) is tied to a specific region in such a way that the regional distribution of the system does not overlap with an area covered by another such system;

(c) does not have a written or standardized form, i.e. does not have officially standardized orthographic and grammatical rules.

Idiolect

Language use characteristic of an individual speaker. This…