There is a somewhat related argument that kids who grow up bilingual also get a harder brain workout that initially slows their language learning due to having

There is a somewhat related argument that kids who grow up bilingual also get a harder brain workout that initially slows their language learning due to having to parse two languages but later gives them an advantage. I think maybe, but seems really hard to measure something like that. My kid is growing up bilingual, with English his stronger language. We both grouch about the "atrocious amalgam of contributions" that is the English language when he wants an explanation why the words 'rough', 'though', 'through', 'thought' and 'plough' all have different pronunciations.