Mainstream scholarship places Bulgar among the "Lir" branch of Turkic languages referred to as Oghur Turkic, Lir-Turkic or, indeed, "Bulgar Turkic", as opposed to the "Shaz"-type of Common Turkic. The "Lir" branch is characterized by sound correspondences such as Oghuric /r/ versus Common Turkic /z/ and Oghuric /l/ versus Common Turkic /š/. As was stated by Al-Istakhri, "The language of the Khazars is different than the language of the Turks and the Persians, nor does a tongue of group of humanity have anything in common with it and the language of the Bulgars is like the language of the Khazars, but the Burtas have another language." The only surviving language from this linguistic group is believed to be Chuvash. Omeljan Pritsak in his study "The Hunnic Language of the Attila Clan" concluded that the language of the Bulgars was from the family of the Hunnic languages, as he calls the Oghur languages. According to the Bulgarian Antoaneta Granberg, "The Hunno-Bulgar language was formed on the northern and western borders of China in the 3rd-5th c. BC." The analysis of the loan-words in Slavonic language shows the presence of direct influences of various language-families: Turkic, Mongolic, Chinese and Iranian. On the other hand, some Bulgarian historians, especially modern ones, link the Bulgar language to the Iranian language group instead, noting the presence of Iranian words in the modern Bulgarian language. According to Raymond Detrez, who is a specialist in Bulgarian history and language, such views are based on anti-Turkish sentiments and the presence of Iranian words in the modern Bulgarian is result of Ottoman Turkish linguistic influence. Indeed, other Bulgarian historians, especially older ones, only point out certain signs of Iranian influence in the Turkic base or indeed support the Turkic theory.
Danube Bulgar
The language of the Danube Bulgars is recorded in a small number of inscriptions, which are found in Pliska, the first capital of Danube Bulgaria, and in the rock churches near the village of Murfatlar, present-day Romania. Some of these inscriptions are written with Greek characters, others with runes similar to the Orkhon script. Most of them appear to have a private character and some were court inventories. Although attempts at decipherment have been made, none of them has gained wide acceptance. These inscriptions in Danube Bulgar are found along with other official ones written in Greek. Greek was used as the official state language of Danube Bulgaria until the 9th century, when it was replaced by Old Bulgarian. The language of the Danube Bulgars is also known from a small number of loanwords in the Old Bulgarian language, as well as terms occurring in Bulgar Greek-language inscriptions, contemporary Byzantine texts, and later Slavonic Old Bulgarian texts. Most of these words designate titles and other concepts concerning the affairs of state, including the official 12-year cyclic calendar. The language became extinct in Danubian Bulgaria in the 9th century as the Bulgar nobility became gradually Slavicized after the Old Bulgarian tongue was declared as official in 893.
Volga Bulgar
The language spoken by the population of Volga Bulgaria is known as Volga-Bulgar. There are a number of surviving inscriptions in Volga-Bulgar, some of which are written with Arabic letters, alongside the continuing use of Orkhon script. These are all largely decipherable. That language persisted until the 13th or the 14th century. In that region, it may have ultimately given rise to the Chuvash language, which is most closely related to it and which is classified as the only surviving member of a separate "Oghur-Turkic" branch of the Turkic languages, to which Bulgar is also considered to have belonged. Still, the precise position of Chuvash within the Oghurfamily of languages is a matter of dispute among linguists. Since the comparative material attributable to the extinct members of Oghuric is scant, little is known about any precise interrelation of these languages and it is a matter of dispute whether Chuvash, the only "Lir"-type language with sufficient extant linguistic material, might be the daughter language of any of these or just a sister branch.
