Arguing in Silence

The other day, in a tram, there were three teenage girls sitting next to me. They dressed like common teenagers here, not too flashy, but not out-of-date either. They must be friends, looking at the way they treated each other. I noticed that they moved their arms and hands a lot, while producing unclear noises from their throat. It didn't take long until I noticed that they are audibly-challenged. I can't read hand-language, but from their expressions, I could assume that they were disagreeing over something. And kept arguing, until they got off at one of the tram stops (which, apparently, was also one of their arguments since they had doubt wheter to get off now or later).
Once they were out of sight, I was pondering to myself. It's nice that these teenagers, in spite of their deafness, can get along with their lifes like other, 'normal', teenagers. They possess confidence. They feel equal. They are fully aware of themselves and their surroundings, without embarrassment of their lack of oral or audio capability.
I like that. And I would love to see more physically-challenged people who have the same independence.