Language isolate
A language isolate is a language that is not known to be related to any other language. Many languages are related to other languages by coming from an older language, and both are still similar. Languages that are related are language families. Most languages are known to belong to a language family. However, some are not known to be related to other languages and are called language isolates.
Some spoken language isolates are Basque, Zuni, Burushaski, Ainu and Mapudungun. Some extinct language isolates are Sumerian, Elamite and Urartian.
