"Brief Literary Encyclopedia" - the most complete encyclopedic publication on fiction of the peoples of the world, literary criticism and literary criticism in Russian, published from 1962 to 1978, answers this question unequivocally:
“Despite the fact that the old literary language in its norms was far from the folk language of language, it existed until the end of the 19th century. Only at the beginning of the 20th century, with the formation of the modern Tatar literary language, literature began to appear on a basis closer to a living folk language. The modern literary Bashkir language arose after the October Revolution on the basis of the concentration of the Kuvakan and Yurmatinsky dialects. Prior to this, the Bashkirs used the Tatar literary language, in which Bashkir literature originally developed. The Bashkirs used the Arabic alphabet, from 1928-29 - Latin and from 1939 - Russian."
feb-web.ru/feb/kle/kle-abc/ke1/ke1-4841.htm
The Literary Encyclopedia, published between 1929-1939 under the editorship of V. M. Fritsche and A. V. Lunacharsky, says the following about the Bashkir language:
“The vocabulary of B. Yaz., Very akin to the Tatar language, is richer than the latter. There are a small number of nominal stems that are absent in the Tatar language. and inherent in the vocabulary of other Turkish languages. - Chuvash, Nogai and much less often others. Dialectical features in the field of phonetics are presented in B. Yaz. very rich, but they are almost completely unexplored. Known dialects: northeastern - Argayash, southern, southwestern, a number of dialects of central Bashkiria: Katai, Zilair. Numerically, the "Kuvakan" dialect is overwhelming, now becoming literary. The dialect he replaced "Jurmatinsky" - lit-th language. "Sterlitamak period" of the development of Bashkir culture [1919-1923] - was formed artificially as a compromise between the Tatarized dialect of the former Yurmatinsky canton, which is closest to Sterlitamak, and the language prevailing in Bashkiria. "Kuvakan" - "deeply Bashkir". Before the revolution, except for the missionary primer, there were no publications in B. Yaz. did not exist. The printed literature had as its first child the book of poems by G. Gabidov “Urae jərdar”, published in early 1919. In March of the same year, a brochure by the Bashkir poet Babich “Why we joined the Reds” appeared in print. In the fall of 1919, she began publishing with articles in the Bashkir and Tatar languages. newspaper "Bashkurdistan". Currently, Bashkiria has a trace. periodicals: the newspaper "Bashkurdistan" and the magazines "Bilim" (Knowledge), "Basqort ajmaqь" (Bashkir tribe), "Haban" (Plow) and "Səsən" (Krasnobay). "In March of the same year, a brochure by the Bashkir poet Babich “Why we joined the Reds” appeared in print. In the fall of 1919, she began publishing with articles in the Bashkir and Tatar languages. newspaper "Bashkurdistan". Currently, Bashkiria has a trace. periodicals: the newspaper "Bashkurdistan" and the magazines "Bilim" (Knowledge), "Basqort ajmaqь" (Bashkir tribe), "Haban" (Plow) and "Səsən" (Krasnobay). "In March of the same year, a brochure by the Bashkir poet Babich “Why we joined the Reds” appeared in print. In the fall of 1919, she began publishing with articles in the Bashkir and Tatar languages. newspaper "Bashkurdistan". Currently, Bashkiria has a trace. periodicals: the newspaper "Bashkurdistan" and the magazines "Bilim" (Knowledge), "Basqort ajmaqь" (Bashkir tribe), "Haban" (Plow) and "Səsən" (Krasnobay)."
feb-web.ru/feb/litenc/encyclop/le1/le1-3761 …