Language isolate

A language isolate, sometimes called an isolated language, is a language that has no demonstrable genetic relationship with any other language. That is, an isolate is a family of one. Basque in Europe, Ainu (if counted as a single language) and Burushaski in Asia, Sandawe and Hadza in Africa, Haida and Zuni in North America, Kanoê and Trumai in South America, Tiwi and possibly Porome in Oceania are examples of language isolates. The exact number of language isolates is unknown due to insufficient data on several languages; that is, there is a fuzzy boundary between language isolates and unclassified languages. Researchers may have differing criteria on how much comparative work needs to be done before concluding that a language is an isolate.

"Isolate" does not mean that a language has no relatives, only that any relationships are too distant to be detectable. Most established families of oral languages – including isolates – are assumed to be related to each other at a time depth too great for us to reconstruct. (See linguistic monogenesis.)

Another possibility is that the language arose independently and does not share a common linguistic genesis with any other language. This possibility is often posited for sign languages that are thought to have developed independently of other oral or sign languages.

In some classifications, a language may be counted as an isolate once all known relatives are extinct. An example is the Ket language spoken in central Siberia, which belongs to the wider Yeniseian family, all the others of which are now extinct. Ket is thus an isolate in the current context. However, most classifications do not count Ket as a language isolate because it does have demonstrable relatives, even if they no longer exist except in recorded data. If those relatives had gone extinct without being recorded, then Ket would be an isolate in the stricter sense.

Isolates may be reclassified as larger families if some of their purported dialects are later judged to be sufficiently different from each other to count as different languages. Examples include the erstwhile isolates of Japanese and Georgian: Japanese is now considered to be the Japonic language family (which includes the Ryukyuan languages), and Georgian to be the Kartvelian language family.

There is a difference between language isolates and unclassified languages, but they can be difficult to differentiate when data is limited. If comparative efforts do prove fruitful, a language previously considered an isolate may be reclassified as being part of a larger language family, as happened with the Yanyuwa language of northern Australia, now 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 particular language is an isolate.