Canada is not just english-speaking, but also french speaking. We have TWO national languages, with equal importance.

This being said, I would suspect the english word gaol comes from the french word geôle.

According to Wiktionary (https://en.wiktionary.org/wiki/gaol), gaol and geôle have a common shared ancestor in Old French/Latin. It's not the result of Canada's multilingual nature.

I stayed in the Ottawa Jail Hostel in the former Carleton County Gaol. The receptionist sure acted like a warden.

https://en.wikipedia.org/wiki/Ottawa_Jail_Hostel