the same thing happens with other languages.  my mother tongue is german.  i lived in paraguay for a few years, where there are lots of german mennonites, many of whom had immigrated before WW2.  they used some turns of phrases, words and pronunciations that seemed quite odd to me.  conversely, when i taught german to spanish-speaking people, my mennonite friends were perplexed why i taught them strange and seemingly useless words - i remember the word "taschenschirm" ("pocket umbrella") - a word that had not even existed when their fathers had left germany, and which had become quite a household word, thanks to a company that produced them and done a great job marketing their product.