language isolate

n. natural language that has no linguistic connection with any other language or is a descendant of an ancestor which is common to any other language (Basque or Korean for example)

A language isolate, in the absolute sense, is a natural language with no demonstrable genealogical (or "genetic") relationship with other living languages; that is, one that has not been demonstrated to descend from an ancestor common to any other language. They are in effect language families consisting of a single language. Commonly cited examples include Basque, Ainu, Burushaski, and Korean, though in each case a minority of linguists claim to have demonstrated a relationship with another language (see Dene-Caucasian, Karasuk, and Altaic, for example).
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