A sacred language, holy language or liturgical language is a language that is cultivated and used primarily for religious reasons by people who speak another, primary language in their daily lives.

An extinct language is a language that no longer has any first-language or second-language speakers, especially if the language also has no living descendants. In contrast, a dead language is a language that no longer has any first-language speakers, but does have second-language speakers, such as Latin. A dormant language is a dead language that still serves as a symbol of ethnic identity to an ethnic group; these languages are often undergoing a process of revitalisation. Languages that have first-language speakers are known as modern or living languages to contrast them with dead languages, especially in educational contexts.