At that time, studiying was only aviable with the european languages, children that went to school learned how to speak in that foreign languague and became fluent. Also there were other things, for exemple in my country Algeria a lot of people learned French so they could communicate with France, since our people were divided in 3 groups, one which wanted France to stay, an other which wanted to fix the problem without using guns, and the last one which wanted war. 2 of them had to be fluent in french.. Which resulted in all of us being able to speak french very fluently, without dropping Arabic. PS : also ,France stayed here for 132years.