Starting a campaign with tyrell in westeros latest version I found that they spoke with arabic accent. I went in descr_sound file and saw that tyrell were set on english accent. So I read that I need to make regenerate files inside data/sound. Here, if I take off any files inside this folder except for event files nothing change; if I take off event file and all the other files inside, that accent then change in the english one but there are no more effects sound, for example in the menu when you click on any buttons (single player, options, etc) you can't hear the typical sound and in campaign when clicking on any buttons too.
So, how is it possible to change accent without having this problem? The guide you can find that says to take sound files from original medieval 2 game and then take off event files does not solve this problem.