After being here for a couple of days, it's my general impression that although French would be the main language used out and about, most Quebecois are quite skilled in the use of English and so if you show any sign of not having a clue in French, they will quickly switch to English.
Case in point, this morning after church, I was talking to a young girl in church. She was curious about the girl standing beside me because she had part of her arm amputated. Imagine that conversation as one of your first in a language you will be attempting to learn! Anyway, as I struggled to comprehend her quick speech, she picked up on the fact that I didn't have much of a clue. After attempting that first conversation, I then introduced myself and asked her name. Easy enough...let's move on to a tougher question. I asked her how old she was. She told me "J'ai onze ans." (I am eleven. I totally understood her.) She followed this sentence with another heavily accented one. After asking her to repeat it several times, I finally told her that I didn't understand. Turns out she was speaking in English, saying "Eeeleevenn." Sheesh, can't even understand my own language these days. :) She thought it quite funny that I didn't understand her when she was speaking in English. I had a good laugh, too.