Metalanguagelanguages

Metalanguagelanguages is a term used to describe languages that function as metalanguages for describing or analyzing other languages. A metalanguage is a language used to talk about, describe, or reason about another language, known as the object language. Metalanguagelanguages therefore are the formal or natural languages and systems employed to specify structure, syntax, semantics, or data formats of other languages.

In linguistics and language study, a metalanguage is used to state grammar rules, translations, glosses, and semantic descriptions. For example, one might explain the syntax of English sentences in English itself or use a separate theoretical language to discuss phonology, morphology, or syntax. The metalanguage serves to make precise statements about the properties of the object language without conflating the two.

In computer science and formal language theory, metalanguages are formal systems used to describe other languages. Well-known examples include Backus-Naur Form (BNF) and Extended Backus-Naur Form (EBNF), which specify the syntax of programming languages. Other metalinguistic formalisms include ABNF, XML Schema, and JSON Schema, which define the structure and validation rules for data formats. These metalanguages enable the design of parsers, compilers, and validators by providing unambiguous rules for the object languages they describe.

Notes on use and limitations: levels of description must be kept separate to avoid circular definitions, and differing metalanguages can introduce interpretive ambiguity if not well defined. Properly used, metalanguagelanguages support precise language specification, analysis, and tool development.

See also: metalanguage, formal language theory, grammar, parsing, BNF, EBNF.