Do you think you could add something to stop the Vietnamese voices from coming from non unsung units?

Yep, definitely.

I'm not planning to change that behaviour of Unsung. They should consider having their own separate items the same way it's done in Global Mobilization CDLC.

If you guys could make a patch for Unsung so that it doesn't retextures and rebrands vanilla items like the watch, the map and the binoculars that would be awesome! I'd love to use Unsung with other mods without it interfering in immersion or stuff like that.