I learned some French in school, and can stumble through some basic conversation, but often get it wrong, much to the amusement of the person I was talking to. In Quebec, what often happened to me is that at this point they would break out the English, which they often spoke very well. Or, they would help me stumble along until we both had a general understanding of what is being communicated. It's kind of fun, actually, and has been useful at times, but the problem is that if you don't use it regularly, you tend to lose most of it.

On a side note, in the 1980s a bunch of us went to the NHRA event in Sanair, Quebec. I was the only one who attempted to speak in french, and typically got the best reactions from the locals. They seemed to appreciate the attempt, even if my french wasn't very good.