The idea that the function of language is its use is commonly ascribed to the Later Wittgenstein. In this paper, I argue that there is textual evidence already coming from the early manuscripts proving that Wittgenstein's philosophical development is culminating in the idea of function as use around 1929–30. I interpret a passage from Ms‐107 in order to show that Wittgenstein's practical turn has sources in different stages of his philosophical development, each of which is dominated by different ideas: the (...) idea of a picture theory; the idea of a phenomenological language and the idea of function as use. (shrink)