Multilingualism is the norm effectively everywhere but the US. Heck, even the kids are multilingual!
I learned my second language (French) starting at 4, my third (Latin) at 11--which I promptly forgot, and my fourth (Spanish) at 12. I reached near fluency in Spanish and have been told by Spaniards that I have a Madrid accent. In university, my Spanish began to rival my French because of the effort I invested in it. So people can do well even later if exposed to native speakers. I think it's never too late to try a new language on.
Patricia Kuhl is the person to Google on foreign phoneme recognition.
