A special type of language that is socially defined, by formality or for specific application in a trade, profession, skill or other social division.’

(Hale & Basides 2013 p.58)

Interlocutor

The audience or person we are addressing.

Repertoire

‘The range of varieties or languages that a speaker has available to use’.

(Crystal 2019 p.521)

Slang

A type of language consisting of words and phrases that are regarded as very informal, are more common in speech than writing, and are typically restricted to a particular context or group of people.