Definition of "sublanguage"

DML is considered a sublanguage of SQL. It's concerned with manipulating data stored in the database. DML consists of four commonly used statements: INSERT, UPDATE, DELETE, and MERGE.

2015, Miguel Cebollero, Michael Coles, Jay Natarajan, Pro T-SQL Programmer's Guide, Apress, page 4

We define sublanguage here as the particular language used in a body of texts dealing with a circumscribed subject area (often reports or articles on a technical speciality or science subfield), in which the authors share a common vocabulary and common habits of word usage.

1982, Richard Kittredge, John Lehrberger, editors, Sublanguage: Studies of Language in Restricted Semantic Domains, Walter de Gruyter, page 27

Sublanguages are usually taken from science and technology domains and are restricted to a particular topic.

1995, Douglas Biber, Dimensions of Register Variation: A Cross-Linguistic Comparison, Cambridge University Press, page 16