Say What?

Can I just say that Vietnamese people must have exquisite hearing. Now, I must admit.. I must be pretty uncultured because unfortunately, I don't have any Vietnamese friends, so I can't ask them directly. But how is it, at the nail salon, that the person looking down at your nails filing them can talk so quietly, and still be heard by their co-worker across the room? I can barely hear them! I swear they're wearing headsets...they must be. When they ask me a question about the length of my nail, sitting less than 2 feet away from me, I have to ask them to repeat their question. And I know they asked me in a louder voice than when they're chatting with each other. How is it possible?! I wish I could hear that well!