Do you know sign language???

Do you know sign language??? A few years ago at CHRISTmas time....I was shopping...and I was stuttering some...and this sales girls asks politely if I knew sign language??? I was sort of taken aback--I was never asked if I knew sign language....1) I aint deaf.....2) I wish I had learned sign language--so I could play it off as being deaf.....should I take that as the salesgirl didnt know any better by asking me if I knew sign language??? Was she trying to help me??? I stutta--Im not deaf!!! Did she think I was deaf because I was stuttering????