Any TTS system requires accurate grapheme tophoneme conversion routines due to the limited pro-nunciation dictionaries. Data driven approaches of-fer the possibility to train new languages withoutthe knowledge of rules. A big problem is to preparehuge databases for the training. In this paper theautomation of the data preparation and the patterngeneration for the training of a neural network is ad-dressed. This automation is language independent,and no native expert is required. The data prepara-tion, the generation of the training patterns and thetraining itself are done completely automatically.