List of Indo-European languages

This is a list of languages in the Indo-European language family. It contains a large number of individual languages, together spoken by roughly half the world's population.
The Indo-European languages include some 449 (SIL estimate, 2018 edition) languages spoken by about 3.5 billion people or more (roughly half of the world population). Most of the major languages belonging to language branches and groups in Europe, and western and southern Asia, belong to the Indo-European language family. This is thus the biggest language family in the world by number of mother tongue speakers (but not by number of languages: by this measure it is only the 3rd or 5th biggest). Eight of the top ten biggest languages, by number of native speakers, are Indo-European. One of these languages, English, is the de facto world lingua franca, with an estimate of over one billion second language speakers. Indo-European language family has 10 known branches or subfamilies, of which eight are living and two are extinct. Most of the subfamilies or linguistic branches in this list contain many subgroups and individual languages. The relationships between these branches (how they are related to one another and branched from the ancestral proto-language) are a matter of further research and not yet fully known. There are some individual Indo-European languages that are unclassified within the language family; they are not yet classified in a branch and could constitute a separate branch. The 449 Indo-European languages identified in the SIL estimate, 2018 edition, are mostly living languages. If all the known extinct Indo-European languages are added, they number more than 800 or close to one thousand. This list includes all known Indo-European languages, living and extinct.
The distinction between a language and a dialect is not clear-cut and simple: in many areas there is a dialect continuum, with transitional dialects and languages. Further, there is no agreed standard criterion for what amount of differences in vocabulary, grammar, pronunciation and prosody are required to constitute a separate language, as opposed to a mere dialect. Mutual intelligibility can be considered, but there are closely related languages that are also mutual intelligible to some degree, even if it is an asymmetric intelligibility. Or there may be cases where between three dialects, A, B, and C, A and B are mutually intelligible, B and C are mutually intelligible, but A and C are not. In such circumstances grouping the three dielects becomes impossible. Because of this, in this list, several dialect groups and some individual dialects of languages are shown (in italics), especially if a language is or was spoken by a large number of people and over a large land area, but also if it has or had divergent dialects.
The ancestral population and language, Proto-Indo-Europeans that spoke Proto-Indo-European, are estimated to have lived about 4500 BCE (6500 BP). At some point in time, starting about 4000 BCE (6000 BP), this population expanded through migration and cultural influence. This started a complex process of population blend or population replacement, acculturation and language change of peoples in many regions of western and southern Eurasia. This process gave origin to many languages and branches of this language family. By around 1000 BCE, there were many millions of Indo-European speakers, and they lived in a vast geographical area which covered most of western and southern Eurasia (including western Central Asia). In the following two millennia the number of speakers of Indo-European languages increased even further. Indo-European languages continued to be spoken in large land areas, although most of western Central Asia and Asia Minor were lost to other language families (mainly Turkic) due to Turkic expansion, conquests and settlement (after the middle of the first millennium AD and the beginning and middle of the second millennium AD respectively) and also to Mongol invasions and conquests (which changed Central Asia ethnolinguistic composition). Another land area lost to non-Indo-European languages was today's Hungary, due to Magyar/Hungarian (Uralic language speakers) conquest and settlement. However, from about AD 1500 onwards, Indo-European languages expanded their territories to North Asia (Siberia), through Russian expansion, and North America, South America, Australia and New Zealand as the result of the age of European discoveries and European conquests through the expansions of the Portuguese, Spanish, French, English and the Dutch. (These peoples had the biggest continental or maritime empires in the world and their countries were major powers.) The contact between different peoples and languages, especially as a result of European colonization, also gave origin to the many pidgins, creoles and mixed languages that are mainly based in Indo-European languages (many of which are spoken in island groups and coastal regions).
Although all Indo-European languages descend from a common ancestor called Proto-Indo-European, the kinship between the subfamilies or branches (large groups of more closely related languages within the language family), that descend from other more recent proto-languages, is not the same because there are subfamilies that are closer or further, and they did not split-off at the same time, the affinity or kinship of Indo-European subfamilies or branches between themselves is still an unresolved and controversial issue and being investigated. However, there is some consensus that Anatolian was the first group of Indo-European (branch) to split-off from all the others and Tocharian was the second in which that happened. Using a mathematical analysis borrowed from evolutionary biology, Donald Ringe and Tandy Warnow propose the following tree of Indo-European branches:
David W. Anthony, following the methodology of Donald Ringe and Tandy Warnow, proposes the following sequence:
The list below follows Donald Ringe, Tandy Warnow and Ann Taylor classification tree for Indo-European branches. quoted in Anthony, David W. (2007), The Horse, the Wheel and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World, Princeton University Press.
Indo-European languages whose relationship to other languages in the family is unclear
Unclassified languages that may have been Indo-European or members of other language families (?)