Most languages are known to belong to language families. An accurately identified family is a phylogenetic unit; that is, all its members derive from a common ancestor. This ancestor is very seldom known directly, since most languages have a very short recorded history. However, it is possible to recover many of its features by applying the comparative method—a reconstructive procedure worked out by 19th century linguist August Schleicher. This can demonstrate the validity of many of the proposed families listed below.
Language families can be divided into smaller phylogenetic units, conventionally referred to as branches of the family, because the history of a language family is often represented as a tree diagram. However, the term family is not restricted to any one level of this "tree"; the Germanic family, for example, is a branch of the Indo-European family. Some taxonomists do restrict the term family to a certain level, but there is little consensus in how to do this. Those who do affix such labels also subdivide branches into groups, and groups into complexes. The terms superfamily, phylum, and stock are applied to proposed groupings of language families whose status as phylogenetic units is generally considered to be unsubstantiated by accepted historical linguistic methods.
The common ancestor of the languages belonging to a language family is known as its protolanguage. For example, the reconstructible protolanguage of the well-known Indo-European family is called Proto-Indo-European. This is not known from written records, since it was spoken before the invention of writing, but sometimes a protolanguage can be identified with a historically known language. Thus, provincial dialects of Latin ("Vulgar Latin") gave rise to the modern Romance languages, so the Proto-Romance language is more or less identical with Latin (if not exactly with the literary Latin of the Classical writers), and dialects of Old Norse are the protolanguage to Norwegian, Swedish, Danish, Faroese and Icelandic.
Languages that cannot be reliably classified into any family are known as language isolates. A language isolated in its own branch within a family, such as Greek within Indo-European, is often also called an isolate, but such cases are usually clarified. For instance, Greek might be referred to as an Indo-European isolate.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Language family".
last update April 28th, 2006