If you download the skins you can simply place the SoundSpeechEnglish.sga in the AciSkins\Archives folder and start the game with the -mod AciSkins parameter, then you will be able to play with the skins and the native Voices.
However it is still odd that the game wont start for you
Ah im stupid, yes sorry its -mod AciSpeech -.-
Ive got multiple modifications, thats why i made that mistake sorry.
The error "Failed to start App" will appear everytime you start the game, BUT with -mod AciSpeech the game will actually start regardless of the error message
1) download the mod <link removed>
2) Extract the AciSpeech.rar to your Steam/steamapps/common/Company of heroes 2 folder
3) Go to your Steam library, right click on Company of Heroes 2, select properties -> set launch options and paste this: -mod AciSpeech
into the text line.
If you dont want to use the mod anymore (or if you encounter any problems) just remove the launch options.
If you experience any problems please let me know.
You need to have your game set to english via steam.
However, since they added a few things with the last patch there are units and speech lines that are still in english (partisans and >one< molotov speech line). Overall it works fine though.