I hadn't thought about this in years, but my mother learned English in Montreal.
My Mexican grandfather worked in a Canadian embassy when my mother was a young child (this would have been mid-1920s). One day her parents put her in the car, drove her to a Catholic boarding school and left her there. She had no idea this was planned and no idea for how long, but being a dutiful child she just did as she was told. She was there for months and one her clearest memories was picking a large bug out of her oatmeal, setting it beside her bowl, then continuing to eat.
So that is where she learned English. And for the rest of her life, my mother had a slight French accent to her English (that really tended to confuse people when they noticed).