Language family
Sound changes are one of the strongest pieces of evidence that can be used to identify a genetic relationship because of their predictable and consistent nature, and through the comparative method can be used to reconstruct proto-languages.
For example, the Mongolic, Tungusic, and Turkic languages share a great deal of similarities that lead several scholars to believe they were related.
[7][8] Lyle Campbell (2019) identifies a total of 406 independent language families, including isolates.
The largest five language families in terms of number of speakers (Indo-European, Sino-Tibetan, Afro-Asiatic, Niger-Congo and Austronesian) make up five-sixths (almost 83.3%) of the world’s population.
The term and the process of language evolution are independent of, and not reliant on, the terminology, understanding, and theories related to genetics in the biological sense, so, to avoid confusion, some linguists prefer the term genealogical relationship.
[16] In some cases, the shared derivation of a group of related languages from a common ancestor is directly attested in the historical record.
For example, this is the case for the Romance language family, wherein Spanish, Italian, Portuguese, Romanian, and French are all descended from Latin, as well as for the North Germanic language family, including Danish, Swedish, Norwegian and Icelandic, which have shared descent from Ancient Norse.
Latin and ancient Norse are both attested in written records, as are many intermediate stages between those ancestral languages and their modern descendants.
Pairs of words that have similar pronunciations and meanings in the two languages are often good candidates for hypothetical cognates.
On the global scale, the site Glottolog counts a total of 423 language families in the world, including 184 isolates.
Within a large family, subfamilies can be identified through "shared innovations": members of a subfamily will share features that represent retentions from their more recent common ancestor, but were not present in the overall proto-language of the larger family.
The term macrofamily or superfamily is sometimes applied to proposed groupings of language families whose status as phylogenetic units is generally considered to be unsubstantiated by accepted historical linguistic methods.
A speech variety may also be considered either a language or a dialect depending on social or political considerations.
However, it is possible to recover many features of a proto-language by applying the comparative method, a reconstructive procedure worked out by 19th century linguist August Schleicher.
For example, the reconstructible common ancestor of the Indo-European language family is called Proto-Indo-European.
Critics focus mainly on the claim that the internal structure of the trees is subject to variation based on the criteria of classification.
[13] Historical glottometry is an application of the wave model, meant to identify and evaluate genetic relations in linguistic linkages.
[13][24] A sprachbund is a geographic area having several languages that feature common linguistic structures.
[25] Shared innovations, acquired by borrowing or other means, are not considered genetic and have no bearing with the language family concept.
It has been asserted, for example, that many of the more striking features shared by Italic languages (Latin, Oscan, Umbrian, etc.)
However, very similar-looking alterations in the systems of long vowels in the West Germanic languages greatly postdate any possible notion of a proto-language innovation (and cannot readily be regarded as "areal", either, since English and continental West Germanic were not a linguistic area).
But legitimate uncertainty about whether shared innovations are areal features, coincidence, or inheritance from a common ancestor, leads to disagreement over the proper subdivisions of any large language family.
Languages that arise in order for two groups to communicate with each other to engage in commercial trade or that appeared as a result of colonialism are called pidgin.
