I know, this is the last time I will bump this but I felt that I needed to clarify the request.
There has been a LONG issue with Dragonborn companions and Guardians, because there are none available in a vanilla game.
Since there are no Dragonborn companions or Guardians available in an un-modded game, Larian never gave them proper facial animations.
If you use a mod to add Dragonborn companions or a Dragonborn Guardian, the face has minimal animation during cinematics and it looks like they are perpetually mumbling.
I would be very grateful if someone corrected Larians oversight and finally fixed the issue.