Audio witihin the game and movies between missions from the original DVD version. Choose your language for the datas_ and datav_ files or just grab them all and copy them in your game folder, default is C:\Program Files (x86)\Steam\steamapps\common\Act of War Direct Action

https://mega.nz/folder/mR1lxYSK#-YL8R31jHs7LvryWYLvhuw

For the in game text, open the file 2710_install.vdf with your notepad and search for language. Replace EN with the one you want DE, ES, FR or IT. Save before closing.

Enjoy