French/German Voices w English Text; What Stops Us?

I have recently, roughly, understood that the Wwise tool and .wem creation process is much more complicated than the good old days when you could just import your own sound files. Hence the existence of only a handful of Music Mods having ever been made.

Still, can someone with a little knowlege explain what I'd come up against if I tried to: A. Back up my French loc audio files. B. Re-install my English loc files. C. Use PFM to replace my English voice files with the French ones? At first glance I'm not seeing any associated bnk files in the French localization, so I'm guessing that the numerical names for the French voice wem files match their English counterparts.

I've probably overlooked a .bnk or other coded file in the French localization, which is specific to the French wem files. OR, maybe I'm misunderstanding how a .wem file works. Otherwise, I'd have expected this approach I'm asking about would've been done by someone else long before now. I've looked for information on this and nobody seems to have discussed it yet. Which I find hard to beleive.

Any knowledgeable answers or insights?

ps: I should add, that if I find out that this task IS doable (without hex-code or such labors), then I'll probably make that mod. First in French, and then, if possible, also using German.

Thanks!

UPDATE:
Well, I looked at the French Loc pack more closely and eventually found those bnk files in audio, advisor, and diplomacy folders when I scrolled down.
Creating a pack using just the audio folder from the backed up french loc, and without the other folders, I was able to enjoy French voices in my game. I only tested it for half an hour in campaign and battle, but it seems to work, bnk files and all.

For anyone who reads this and is totally new to modding, what I'm talking about IS:

Going into the properties for your Attila game via Steam, change your language to French (German voice is also supported), back up the local_fr.pack file, change back to English again. Use Pack File Manager ver 5.2.4 to open the local_fr.pack file, go to options and enable editing, delete all folders other than audio, change the file type to Movie, save it with a new name like "French_Voice_Mod", and place it in your Total War Attila/data directory.

Again, I've not tested this extensively, and not sure if english subtitles are actually functional outside of the usual advisor/diplomacy UI. But I thought I'd report my finiding JIC anyone else wanted to try this.
I don't know if this process could work in reverse (French/German UI text w English voices) since the English files are the default audio, and the French/German files are already designed to overwrite.

It's a pity that TWA only has voice support for English, French, and German. I miss the days when you could get a multitude of authentic languages to mod with, like we did for M2TW. Ah well.