I haven't seen it in the options, but is there a way to have a different audio language from the texts ? Like playing with English audio and French text ?
There is no option to set the audio language different from the text. When you change the language of your game client, the NPC voice-overs will automatically change to the corresponding language.
On PC/Mac, you can change the language by selecting their preferred language in the game launcher under Settings (the gear icon) then Options. In the drop-down list under Language you can then choose between English, French, and German. This will result in the additional files being downloaded.