A language isolate, in the absolute sense, is a natural language with no demonstrable genealogical (or "genetic") relationship with other languages, one that has not been demonstrated to descend from an ancestor common with any other language. Language isolates are in effect language families consisting of a single language. Commonly cited examples include Basque, Sumerian, and Elamite, though in each case a minority of linguists claim to have demonstrated a relationship with other languages.
Some sources use the term "language isolate" to indicate a branch of a larger family with only one surviving member. 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 (such as the Romance, Indo-Iranian, Celtic, Slavic or Germanic branches), but instead form independent branches. Similarly, within the Romance languages, Sardinian is a relative isolate. However, without a qualifier, isolate is understood to mean having no demonstrable genetic relationship to any other language.
Some languages once seen as isolates may be reclassified as small families. This happened with Japanese (now included in the Japonic family along with Ryukyuan languages such as Okinawan), Ainu in Ainu languages and Korean in Koreanic languages with Jeju language. The Etruscan language of Italy has long been considered an isolate, but some have proposed that it is related to the so-called Tyrsenian languages, an extinct family of closely related ancient languages proposed by Helmut Rix in 1998, including the Rhaetian language, formerly spoken in the central Alps, and the Lemnian language, formerly spoken on the Greek island of Lemnos.
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 is an isolate or not.
With few exceptions, all of Africa's languages have been gathered into four major phyla: degree of endangerment of the language, according to the definitions of the UNESCO Atlas of the World's Languages in Danger. "Vibrant" languages are those in full use by speakers of every generation, with consistent native acquisition by children. "Vulnerable" languages have a similarly wide base of native speakers, but a restricted use and the long-term risk of language shift. "Endangered" languages are either acquired irregularly or spoken only by older generations. "Moribund" languages have only a few remaining native speakers, with no new acquisition, highly restricted use, and near-universal multilingualism. "Extinct" languages have no native speakers, but are sufficiently documented to be classified as isolates.
With few exceptions, all of Africa's languages have been gathered into four major phyla: Afroasiatic, Niger–Congo, Nilo-Saharan and Khoisan. However, the genetic unity of some language families, like Nilo-Saharan, is questionable, and so there may be many more language families and isolates than currently accepted.[by whom?] Data for several African languages, like Kwadi and Kwisi, are not sufficient for classification. In addition, Jalaa, Shabo, Laal, Kujargé, and a few other languages within Nilo-Saharan and Afroasiatic-speaking areas may turn out to be isolates upon further investigation. Defaka and Ega are highly divergent languages located within Niger-Congo-speaking areas, and may also possibly be language isolates.
|Bangime||2,000||Vibrant||Mali||Spoken in the Bandiagara Escarpment. Used as an “Papuasphere” centered in New Guinea includes as many as 37 isolates. (The more is known about these languages in the future, the more likely it is for these languages to be later assigned to a known language family.) To these, one must add several isolates found among non-Pama-Nyungan languages of Australia: