Spoken language

A spoken language is a structured system of communication that is produced with speech, sometimes specifically also called an oral language or vocal language to differentiate it from written language and possibly from sign language. However, the term "spoken language" may also be used to incorporate sign languages, referring to any natural language or forms of language other than transcribed or written ones. Spoken (including signed) language is traditionally ephemeral, only communicated once, and not retrievable after being produced—notwithstanding modern voice-recording and audiovisual technology. This differs from written language, whose explicit purpose is to represent an enduring message on a physical surface. The major written languages of the world developed secondarily from naturally-emerged spoken languages. As such, spoken languages are usually the more relevant focus to the study of human history, the origin of language, and language acquisition.