I've downloaded the game but the speech is still english despite the fact the front page said that Italian speech is aviable. Is that normal?

If you use a browser when you download a game did you try to select the language above that said italiano

The game is in Italian but the voices are in English, the frontpage clearly says that Italian audio is aviable.

Oh yeah i see that on the front page, don't know if there are any settings anywhere for that.
Maybe try contacting support about this.

There isn't the Italian audio in any Gothic games. They were never dubbed in Italian.
It's always English speech with Italian subtitles, so there's a mistake in the store page.