Mongolization
Mongolization is a cultural and language shift whereby populations adopt the Mongolic languages or culture. Kazakhs in Mongolia went through partial Mongolization.
Historically, groups such as Ongud, Keraites, Naimans and Merkits were Mongolized Turkic groups. Tanguts, who speak the Sino-Tibetan language but later became Mongolian, can be given as an example. Khotons are Mongolic but formerly were of Turkic ethnicity.