I would want to hug her - I have known several people like this who feel embarrassed, afraid to share and a bit lonely.
id be impressed if i had never realized
I would want to know how I could help. Make sure I didn't hide my mouth when we talked face to face, use Skype even if we lived close so she/you could read my lips.
Tell her that she's still the same person to me and I won't treat her any differently because of it. Just because she's deaf doesn't make her any less of an important person in my life. I'd also probably ask why she didn't tell me before and give her a hug if she wants one. :)
id be like, how come u always heard me when i talk to you?
I'd tell her I still love her and don't see her any differently. I would secretly feel bad that she couldn't tell me before(I totally understand though, unfortunately there are people that would treat someone differently).
Your question brings me the image of someone who is never listen to, whom nobody cares when he talks... And that by knowing that his friend is deaf become aware of how much he is ignored.
I'd let her know that she is still the same person to me, nothing has changed in my opinion of her.
Jawdrop. Followed by the spanking of her life.