Hmmm, Ummm, & Uh-Uh

Our little 8 year old, I mean practically 2 year old has started to use speech disfluencies. (I had no idea what hmmm, ummm, and uh-uh were called and had to look them up and found they are disfluencies. Interesting. I learned something new today...and maybe so did you!) When asked a question that she doesn't immediately know the answer to, Emma will think about it while saying "Ummmm." Every once in a while, she'll use "hmmm" when something perplexes her. In the last week or so, instead of answering no, she has started to use "uh-uh." It was cute the first couple times, now we are starting to find it annoying and bordering on rude. We're pretty sure that she picked it up at daycare. We're currently trying to get her to use no, thank you instead.