As an African-American, what do you think when someone comments on your speech or articulation?

I'm a mixed African-American teenager (16) and I recently received a compliment stating that I am "Very quiet, articulate, and approachable". Of course this is a very nice thing to say, and the very same thing has been said to me many times before. I actually had talked on the phone with a friend of my mom's (My mom is very light-skinned, mistaken for white all the time) I met her in person and my mom told me she said "I had no idea your daughter was darker. She sounded different on the phone" We both though of this, not as racist, but just ignorance. A bit of a back handed compliment, wouldn't you say? Have you ever had an experience like this? If you have, please share :) (You don't have to be black to have experienced this either)