Language Isolate

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

With context, a language isolate may be understood to be relatively isolated. For instance, Albanian, Armenian and Greek are commonly called 'Indo-European isolates'. While part of the Indo-European family, they do not belong to any established branch (like the Romance, Indo-Iranian, Slavic or Germanic branches), but instead form independent branches of their own. Similarly, within the Romance languages, Sardinian is a relative isolate. However, without a qualifier, "isolate" is understood to be in the absolute sense.

Some languages have become isolates after all their known relatives became extinct. The Pirahã language of Brazil is one such example, the last surviving member of the Mura family. Others, like Basque, have been isolates for as long as their existence has been documented. The opposite also occurs; languages once seen as isolates may be reclassified as small families. This happened when the Japonic family was formulated after it was recognized that certain Japanese "dialects", such as Okinawan, were distinct languages.

Language isolates may be seen as a special case of unclassified languages, that remain unclassified even after extensive efforts. If such efforts eventually do prove fruitful, a language previously considered an isolate may no longer be considered one, as happened with the Yanyuwa language of northern Australia, which has been placed in the Pama–Nyungan family. Since linguists do not always agree on whether a genetic relationship has been demonstrated, it is often disputed whether a language constitutes a true isolate or not.