In informatics, natural language processing, and machine translation, a sublanguage is the language of a restricted domain, particularly a technical domain.
[1][2][3] This is a specific term for what in most linguistic study is referred to a language variety or register.
A sublanguage may be restricted syntactically (it accepts a subgrammar of the original language), and/or semantically (the set of possible outcomes for any given program is a subset of the possible outcomes in the original language).
[6] In relational database theory, the term "sublanguage", first used for this purpose by E. F. Codd in 1970, refers to a computer language used to define or manipulate the structure and contents of a relational database management system (RDBMS).
In 1985, Codd encapsulated his thinking in twelve rules which every database must satisfy in order to be truly relational.