Here is the case: we created the Chinese version by choosing the alert contents, and it (by default) replaced the original voice pack.
Is it possible to give users the opportunity to choose the voice pack (like what DBM is doing)?
Or is it possible to introduce the Chinese version to your users?

The translations can be found here...
https://github.com/soniaforme/Bigwigs-Voice
The .ogg files can be found here...
https://u12874421.ctfile.com/fs/12874421-311877384

Looking forward to your reply.

@sehra how is it you generate the ogg files?

one way would be to add a custom folder and configure to load the custom folder by config, having different .ogg files in there. Then people, depending on the ease to generate the ogg files, can release their custom versions of 'em and for a user to install it would mean to download to the custom folder

The files are generated using tools/generate.txt to get WAV files, then tools/encode.txt to make the final OGG files.

Looking at the code in BigWigs it doesn't seem possible to have multiple voice packs installed right now. There was some work done in the area so it might be possible in the future.

For now, the easiest way to get different voice packs working is to make a separate addon and copy Core.lua to that. As long as the sound files are named the same and the two calls are made to register the addon it should work fine.