natural languages [Note from Eric. The remaining edits were made by Ruth Loew of ETS. She has a strong background in both linguistics and sign language]
languages whose rules have evolved through usage within human communities and which are used by humans to communicate, including spoken, written, and signed languages
We have changed the term from "natural language" to "human language" and have updated the definition.
language that is spoken, written or signed (visually or tactilely) by humans to communicate with one another
Note: See also sign language.