As a citizen of Turkey you need a tourist visa in order to do a language course in Germany. A tourist visa allows you to stay for 90 days. More on the website of the German Embassy in Ankara.
GLS visa support
GLS will send an invitation document for the visa application.
In the invitation we have to confirm, that all costs have been taken care of - thus please note that we can send out the invitation only after having received full payment from you. In case of visa rejection, the full amount will be refunded except for a handling fee of Euro 200.