What is a metalanguage?

A metalanguage is essentially a language that is used to describe, define, or analyze another language. In the context of programming, it can refer to a language that helps in specifying the syntax, semantics, and structure of programming languages, markup languages, or any set of rules. By serving as a means to talk about languages themselves, metalanguages enable researchers and developers to create new programming languages or systems that can interpret and process other languages.

For instance, in computing, languages like BNF (Backus-Naur Form) or EBNF (Extended Backus-Naur Form) are considered metalanguages because they provide the necessary formalism to describe the syntax of programming languages. This is significant in the development of compilers and interpreters. Recognizing the function of a metalanguage can help one appreciate how various programming tools and languages interact and are structured.