Not a native speaker, but Quebecois, especially spoken, can involve pretty deep differences in grammar and syntax. Much more than the difference between British and American English.
Example:
Contractions: "M'va le mettre s'a table." = "Je vais le mettre sur la table."
Shortenings: "J'avais plus de nourriture faque chui allé à l'épicerie." = "J'avais plus de nourriture donc je suis allé au marché."
Question particle: "Il veut-tu quelque chose à manger?" = "Veut-il quelque chose à manger?"
I think it's closer to African American Vernacular English (AAVE) or Scots. Most people who speak AAVE/Scots can code switch to standard British or American English, but not vice versa. Some people even seem to hold similar class and discriminatory connotations, unfortunately.