Alex, yes, please feel free to follow up about our shared interests. Perhaps some of my writing on those interests, updated after I read the sources you suggest

Alex, yes, please feel free to follow up about our shared interests. Perhaps some of my writing on those interests, updated after I read the sources you suggest, will show up either here on HN as FAQ posts or as new pages on my personal website, or both. To answer your direct question, my anecdotal observation is that people who are native bilinguals enjoy a life-long advantage in further language learning, which makes sense on theoretical grounds. I'm not sure to what degree this hypothesis has been put to the test in the research literature on language acquisition, some of which I have read.