The problem with Canadian French is not really different words or grammar but the pronunciation/accent (though there are also quite a number of words and expressions that are different). I've been in Quebec only for a few short stays, so most of my experience comes from movies, radio, Youtube videos, podcasts, etc.. But I can assure you, that there is a clear difference between 'standard Quebec French' and standard Metropolitan French. You won't mistake one for the other.
Overall, I have noticeably more problems understanding les Québécois. If they go full throttle colloquial, my level of understanding might drop below 50%. And that is not just me as a non-native speaker, many native European French speakers also have some trouble understanding le français québécois.
Among the differences is a shift of how the vowels are pronounced (eg, 'a' sometimes turns into 'o'), generally things become more nasal. A number of contractions and omissions are added and 's' and 'z' sounds are inserted when a 'd' or 't' is followed by a 'u' or 'i'. A
few examples:
- Il est malade => y'est malade
- Je suis fatigué => Chu fatigué
- Je ne serai pas à la fête de Laura => J’s’rai pô à’ fête à Laurô.
- C’est dur à dire => C’est dzur à dzire.
- Toi tu vas savoir ce que je pense => Toé tu vô savoère c’que j’pense
- As-tu déjà vu ça => Tatu djavu ça
Two relatively random examples of first-person Youtube channels: one from
France and one from
Québec. Even if you don't speak French, you probably will notice that they sound quite different. Since Siri is about understanding spoken language, I am not very surprised that Siri requires additional training to understand les Québécois.