The Turkic languages are a language family of at least thirty-five^[2] documented languages, spoken by the Turkic peoples of Eurasia from Eastern Europe, the Caucasus, Central Asia, and West Asia all the way to North Asia (particularly in Siberia) and East Asia. The Turkic languages originated in a region of East Asia spanning Western China to Mongolia, where Proto-Turkic is thought to have been spoken, according to one estimate, around 2,500 years ago,^[3] from where they expanded to Central Asia and farther west during the first millennium.^[4]

Turkic languages are spoken as a native language by some 170 million people, and the total number of Turkic speakers, including second language speakers, is over 200 million.^[5][6][7] The Turkic language with the greatest number of speakers is Turkish, spoken mainly in Anatolia and the Balkans; its native speakers account for about 40% of all Turkic speakers.^[4]

Characteristic features such as vowel harmony, agglutination, and lack of grammatical gender, are universal within the Turkic family.^[4] There is also a high degree of mutual intelligibility among the various Oghuz languages, which include Turkish, Azerbaijani, Turkmen, Qashqai, Gagauz, Balkan Gagauz Turkish, and Oghuz-influenced Crimean Tatar.^[8] Although methods of classification vary, the Turkic languages are usually considered to be divided equally into two branches: Oghur, the only surviving member of which is Chuvash, and Common Turkic, which includes all other Turkic languages including the Oghuz subbranch.

Turkic languages show some similarities with the Mongolic, Tungusic, Koreanic, and Japonic languages. These similarities led some linguists to propose an Altaic language family, though this proposal is widely rejected by historical linguists.^[9][10] Apparent similarities with the Uralic languages even caused these families to be regarded as one for a long time under the Ural-Altaic hypothesis.^[11][12][13] However, there has not been sufficient evidence to conclude the existence of either of these macrofamilies, the shared characteristics between the languages being attributed presently to extensive prehistoric language contact.

Turkic languages are null-subject languages, have vowel harmony, extensive agglutination by means of suffixes and postpositions, and lack of grammatical articles, noun classes, and grammatical gender. Subject–object–verb word order is universal within the family. The root of a word is basically of one, two or three consonants.

The homeland of the Turkic peoples and their language is suggested to be somewhere between the Transcaspian steppe and Northeastern Asia (Manchuria)^[14], with genetic evidence pointing to the region near South Siberia and Mongolia as the "Inner Asian Homeland" of the Turkic ethnicity.^[15] Similarly several linguists, including Juha Janhunen, Roger Blench and Matthew Spriggs, suggest that Mongolia is the homeland of the early Turkic language.^[16]

Extensive contact took place between Proto-Turks and Proto-Mongols approximately during the first millennium BC; the shared cultural tradition between the two Eurasian nomadic groups is called the "Turco-Mongol" tradition. The two groups shared a similar religion-system, Tengrism, and there exists a multitude of evident loanwords between Turkic languages and Mongolic languages. Although the loans were bidirectional, today Turkic loanwords constitute the largest foreign component in Mongolian vocabulary.^[17] The most famous of these loanwords include "lion" (Turkish: aslan or arslan; Mongolian: arslan), "gold" (Turkish: altın; Mongolian: altan or alt), and "iron" (Turkish: demir; Mongolian: tömör).

Some lexical and extensive typological similarities between Turkic and the nearby Tungusic and Mongolic families, as well as the Korean and Japonic families (all formerly widely considered to be part of the so-called Altaic language family) has in more recent years been instead attributed to prehistoric contact amongst the group, sometimes referred to as the Northeast Asian sprachbund. A more recent (circa first millennium BCE) contact between "core Altaic" (Turkic, Mongolic, and Tungusic) is distinguished from this, due to the existence of definitive common words that appear to have been mostly borrowed from Turkic into Mongolic, and later from Mongolic into Tungusic, as Turkic borrowings into Mongolic significantly outnumber Mongolic borrowings into Turkic, and Turkic and Tungusic do not share any words that do not also exist in Mongolic.

Alexander Vovin (2004, 2010)^[18][19] notes that Old Turkic had borrowed some words from the Ruan-ruan language (the language of the Rouran Khaganate), which Vovin considers to be an extinct non-Altaic language that is possibly a Yeniseian language or not related to any modern-day language.

Turkic languages also show some Chinese loanwords that point to early contact during the time of proto-Turkic.^[20]

Robbeets (et al. 2015 and et al. 2017) suggest that the homeland of the Turkic languages was somewhere in Manchuria, close to the Mongolic, Tungusic and Koreanic homeland (including the ancestor of Japonic), and that these languages share a common "Transeurasian" origin.^[21]

The first established records of the Turkic languages are the eighth century AD Orkhon inscriptions by the Göktürks, recording the Old Turkic language, which were discovered in 1889 in the Orkhon Valley in Mongolia. The Compendium of the Turkic Dialects (Divânü Lügati't-Türk), written during the 11th century AD by Kaşgarlı Mahmud of the Kara-Khanid Khanate, constitutes an early linguistic treatment of the family. The Compendium is the first comprehensive dictionary of the Turkic languages and also includes the first known map of the Turkic speakers' geographical distribution. It mainly pertains to the Southwestern branch of the family.^[22]

The Codex Cumanicus (12th–13th centuries AD) concerning the Northwestern branch is another early linguistic manual, between the Kipchak language and Latin, used by the Catholic missionaries sent to the Western Cumans inhabiting a region corresponding to present-day Hungary and Romania. The earliest records of the language spoken by Volga Bulgars, the parent to today's Chuvash language, are dated to the 13th–14th centuries AD.

With the Turkic expansion during the Early Middle Ages (c. 6th–11th centuries AD), Turkic languages, in the course of just a few centuries, spread across Central Asia, from Siberia to the Mediterranean. Various terminologies from the Turkic languages have passed into Persian, Hindustani, Russian, Chinese, and to a lesser extent, Arabic.^[23]

The geographical distribution of Turkic-speaking peoples across Eurasia since the Ottoman era ranges from the North-East of Siberia to Turkey in the West.^[24] (See picture in the box on the right above.)

For centuries, the Turkic-speaking peoples have migrated extensively and intermingled continuously, and their languages have been influenced mutually and through contact with the surrounding languages, especially the Iranian, Slavic, and Mongolic languages.^[25]

This has obscured the historical developments within each language and/or language group, and as a result, there exist several systems to classify the Turkic languages. The modern genetic classification schemes for Turkic are still largely indebted to Samoilovich (1922).

The Turkic languages may be divided into six branches:^[26]

In this classification, Oghur Turkic is also referred to as Lir-Turkic, and the other branches are subsumed under the title of Shaz-Turkic or Common Turkic. It is not clear when these two major types of Turkic can be assumed to have actually diverged.^[27]

With less certainty, the Southwestern, Northwestern, Southeastern and Oghur groups may further be summarized as West Turkic, the Northeastern, Kyrgyz-Kipchak and Arghu (Khalaj) groups as East Turkic.^[28]

Geographically and linguistically, the languages of the Northwestern and Southeastern subgroups belong to the central Turkic languages, while the Northeastern and Khalaj languages are the so-called peripheral languages.

Hruschka, et al. (2014)^[29] use computational phylogenetic methods to calculate a tree of Turkic based on phonological sound changes.

The following isoglosses are traditionally used in the classification of the Turkic languages:^[30][26]

Additional isoglosses include:

*In the standard Istanbul dialect of Turkish, the ğ in dağ and dağlı is not realized as a consonant, but as a slight lengthening of the preceding vowel.

The following table is based upon the classification scheme presented by Lars Johanson (1998)^[33]

The following is a brief comparison of cognates among the basic vocabulary across the Turkic language family (about 60 words).

Empty cells do not necessarily imply that a particular language is lacking a word to describe the concept, but rather that the word for the concept in that language may be formed from another stem and is not a cognate with the other words in the row or that a loanword is used in its place.

Also, there may be shifts in the meaning from one language to another, and so the "Common meaning" given is only approximate. In some cases the form given is found only in some dialects of the language, or a loanword is much more common (e.g. in Turkish, the preferred word for "fire" is the Persian-derived ateş, whereas the native od is dead). Forms are given in native Latin orthographies unless otherwise noted.

An endangered language, or moribund language, is a language that is at risk of falling out of use as its speakers die out or shift to speaking another language. Language loss occurs when the language has no more native speakers and becomes a "dead language".

Fifteen endangered Turkic languages exist in Russia:^{[44] [45]}

In Qinghai (Amdo), the Salar language has a heavy Chinese and Tibetan influence.^[46] Although of Turkic origin, major linguistic structures have been absorbed from Chinese. Around 20% of the vocabulary is of Chinese origin, and 10% is also of Tibetan origin. Yet the official Communist Chinese government policy deliberately covers up these influences in academic and linguistics studies, trying to emphasize the Turkic element and completely ignoring the Chinese in the Salar language.^[47] The Salar language has taken loans and influence from neighboring varieties of Chinese.^[48] It is neighboring variants of Chinese which have loaned words to the Salar language.^[48] In Qinghai, many Salar men speak both the Qinghai dialect of Chinese and Salar. Rural Salars can speak Salar fluently while urban Salars often assimilate into the Chinese speaking Hui population.^[49]

Ethnologue and ISO list an Iranian language "Khalaj" with the same population,^[50] but Glottolog states it does not exist.^[51] The Khalaj speak their Turkic language and Persian, and the supposed Iranian language of the Khalaj is spurious.^[52]

Khorasani Turkic (Khorasani Turkic: خراسان تركچىسى, Pronunciation: [xorɑsɑn tyrktʃesi]; Persian: Zebān-e Torkī-ye Xorāsānī زبان ترکی خراسانی‎) is an Oghuz Turkic language spoken in northern North Khorasan Province and Razavi Khorasan Province in Iran. Nearly all Khorasani Turkic speakers are also bilingual in Persian.^[53]

^[54]

Many Turkic languages have gone extinct in Afghanistan. ^[55]

In 1980, Saddam Hussein's government adopted a policy of assimilation of its minorities. Due to government relocation programs, thousands of Iraqi Turkmen were relocated from their traditional homelands in northern Iraq and replaced by Arabs, in an effort to Arabize the region.^[56] Furthermore, Iraqi Turkmen villages and towns were destroyed to make way for Arab migrants, who were promised free land and financial incentives. For example, the Ba'th regime recognised that the city of Kirkuk was historically an Iraqi Arab city and remained firmly in its cultural orientation.^[57] Thus, the first wave of Arabization saw Arab families move from the centre and south of Iraq into Kirkuk to work in the expanding oil industry. Although the Iraqi Turkmen were not actively forced out, new Arab quarters were established in the city and the overall demographic balance of the city changed as the Arab migrations continued.^[57]

Several presidential decrees and directives from state security and intelligence organizations indicate that the Iraqi Turkmen were a particular focus of attention during the assimilation process during the Ba'th regime. For example, the Iraqi Military Intelligence issued directive 1559 on 6 May 1980 ordering the deportation of Iraqi Turkmen officials from Kirkuk, issuing the following instructions: "identify the places where Turkmen officials are working in governmental offices [in order] to deport them to other governorates in order to disperse them and prevent them from concentrating in this governorate [Kirkuk]".^[58] In addition, on 30 October 1981, the Revolution's Command Council issued decree 1391, which authorized the deportation of Iraqi Turkmen from Kiruk with paragraph 13 noting that "this directive is specially aimed at Turkmen and Kurdish officials and workers who are living in Kirkuk".^[58]

As primary victims of these Arabization policies, the Iraqi Turkmen suffered from land expropriation and job discrimination, and therefore would register themselves as "Arabs" in order to avoid discrimination.^[59] Thus, ethnic cleansing was an element of the Ba'thist policy aimed at reducing the influence of the Iraqi Turkmen in northern Iraq's Kirkuk.^[60] Those Iraqi Turkmen who remained in cities such as Kirkuk were subject to continued assimilation policies;^[60] school names, neighbourhoods, villages, streets, markets and even mosques with names of Turkic origin were changed to names that emanated from the Ba'th Party or from Arab heroes.^[60] Moreover, many Iraqi Turkmen villages and neighbourhoods in Kirkuk were simply demolished, particularly in the 1990s.^[60]

The Turkic language family is currently regarded as one of the world's primary language families.^[61] Turkic is one of the main members of the controversial Altaic language family. There are some other theories about an external relationship but none of them are generally accepted.

The possibility of a genetic relation between Turkic and Korean, independently from Altaic, is suggested by some linguists.^[62][63][64] The linguist Kabak (2004) of the University of Würzburg states that Turkic and Korean share similar phonology as well as morphology. Yong-Sŏng Li (2014)^[65] suggest that there are several cognates between Turkic and Old Korean. He states that these supposed cognates can be useful to reconstruct the early Turkic language. According to him, words related to nature, earth and ruling but especially to the sky and stars seem to be cognates.

The linguist Choi^[66] suggested already in 1996 a close relationship between Turkic and Korean regardless of any Altaic connections:

Many historians also point out a close non-linguistic relationship between Turkic peoples and Koreans.^[67] Especially close were the relations between the Göktürks and Goguryeo.^[68]

Some historians and linguists suggest a link between Turkic languages and some Native American languages.^[69] Although these claims get some support from genetic studies, they are generally rejected because of the lack of linguistic evidence.^[70]

Some linguists suggested a relation to Uralic languages, especially to the Ugric languages. This view is rejected and seen as obsolete by mainstream linguists. Similarities are because of language contact and borrowings mostly from Turkic into Ugric languages. Stachowski (2015) states that any relation between Turkic and Uralic must be a contact one.^[71]