Or secondary language. In the localization of Windows-based programs, a variant of the primary language, defined by the locale. For example, if English is the the primary language, American, British, Australian, New Zealand, Canadian, and Ireland are the possible locales that determine the sublanguage. See also language identifier (ID).

a language used to communicate in a specialized technical domain or for a specialized purpose, for example, the language of weather reports, expert scientific polemic or other modes of scientific discourse, user or maintenance manuals, drug interaction reports, etc. Such language is characterised by the high frequency of specialized terminology and often also by a restricted set of grammatical patterns. The interest is that these properties make sublanguage texts easier to translate automatically.

A language constructed from another language by eliminating concepts (for example mathematical or musical) and/or grammatical rules (for example subordinate clauses). Many books implicitly define sublanguages by using a restricted vocabulary and an incomplete grammatical repertoire.

a form of human communication that is domain specific, appropriate to that domain and, consequently, highly efficient