For English, say English. A number has been found for Holiday Inn in Ste. Even with my very imperfect French accent, the service was somehow able to pick up the correct names entirely. Friends with noticable accents also have no trouble using the service. The first thing that makes Bell Canada's Directory Assistance service so useful is that it has a clearly defined function.
Users call for one reason only, and that is, to find phone numbers for people or businesses.
The second thing that makes the service so useful is that it actually works with the medium of telephone communication. Most services require button presses, which is not something that users typically do during calls. I am not sure whether a human listens to the user's responses, or whether voice recognition software is interpreting his words. In any case, the user doesn't care. He is easily able to use the service and more quickly reach his personal goals, whatever they may be.