The writing at the bottom of this painting is not French. Just as a representation of a pipe is not a pipe, the representation of a language is not a language.

A written language is the representation of a language by means of a writing system.

Written language is an invention, whereas spoken language has evolved along with homo sapiens. Children will instinctively learn or create spoken (or gestural) languages. However, written language must be taught.

Written language always appears as a complement to a specific natural language (English, French, American Sign Language, etc.) and no purely written languages (with the exception of computer languages, which are not natural languages) exist. Nevertheless many extinct languages are in effect purely written, since the written form is all that survives.