I, surprisingly, can prounounce words fairly well. What I would consider ill-pronounciation is when I start talking with a Boston accent...despite my being at nearly the opposite end of the state lol.
There are a few words such as Manhatten that I cannot, for the life of me, say without a Boston accent. Luckily, there aren't many of those words and I don't have to say Manhatten on a daily basis lol. And no, I can say "park", "car" and "Harvard yard" just fine lol.