Around the end of 19th century a new paradigm arose in philosophy known as the "linguistic turn". Philosophers, like Gottlob Frege, were focused on analyzing language and formalized its logical structure in order to distinguish between absurd, meaningless, and meaningful sentences hoping to make misunderstandings disappear.

Wittgenstein's work was strongly influencing this kind of philosophy. In his early stage he was a supporter of an "ideal language". After finishing his "Tractatus Logico-Philosophicus" and keeping silent for some while (he believed he had solved all essential questions) Wittgenstein again became interested in philosophy. But now his interest was devoted to "normal language". Instead of searching for some ideal structure behind language he took it then as it is in the first place, namely as a performative act - a language game. I will talk about some basic ideas of Wittgenstein's later philosophy which will give some background for his understanding of mathematics.