There are illegal immigrants in Canada. Some have been here for 10 years or more and do speak English and have jobs and Canadian kids, and Canadian spouses who can't afford to sponsor them legally because they make just enough for bills and/or don't understand the legal immigration process, or can't afford to take time off work to get the papers done.

If it was easier for employers to sponsor immigrants on work permits then maybe these people wouldn't be illegal.

Illegal immigration happens when the businesses hire illegal immigrants due to not wanting to pay them as much or not wanting to bother proving to the government that there's a valid reason they didn't hire a Canadian for the job.

It also happens when spouses are denied citizenship even though they already have children here. Permanent residency and the ability to work legally should be a result of marriage, with only a small filing fee and instant processing (if the person's a criminal it would be easy to apprehend them after that - easier than it is now when the criminals are just invisible along with everyone else in the underground economy). Actual citizenship should be a bit harder, but not nearly as difficult as it is now.

If it wasn't necessary for families to stay together illegally in order to stay together, and if businesses had an easier time hiring foreign workers, it'd be only legal immigration happening.