The article, based on an analysis of scientific works on one of the pressing issues of the Turkic languages - verb-forming affixes, shows that in early studies they were studied formally, in connection with morphology. And modern scientific achievements require the study of not only verb-forming, but also all word-forming affixes in a functional-semantic sense, based on the semantics that arose as a result of the relationship between the producing and derived roots. Based on this, the author shows the dynamics of the development of the study of verb-forming affixes as evidence of the advancement of the research of the word-forming system of Turkic languages.