Sign Linguistics

Language change can be internal or external.

Internal changes arise from the internal, phonological rules of the language. Rules simplifying the language cause it to change, but there is no influence from outside the language (from people or society).

External changes are far more major and arise because of outside influences of people or society. For example the language users might borrow new signs from other languages because of language contact, or may need to make new signs because of new inventions or new concepts.