What events led to the fact that many peoples of the Volga region, the Caucasus, Central Asia and Siberia

What events led to the fact that many peoples of the Volga region, the Caucasus, Central Asia and Siberia now speak similar languages of the Turkic group? When did these events take place?

The languages of the Turkic group spread widely in the territories adjacent to the Great Steppe, when these lands were united several times by the powers of the Turkic-speaking nomads (Huns in the II century BC, Turkuts in the 6th century AD, Koktürks in the 7th century, Uighurs in the 9th century, Seljuks and Cumans in the XI century). The northernmost of the Turkic-speaking peoples are the Yakuts, the southernmost and youngest are the Turks, the easternmost and most ancient are the Koreans, and the westernmost are the Gagauz.