The man who taught the course was incredible. He had kids taking his classes, just so they could observe him unconsciously floating into another language. He would get so engrossed in his subject matter, that he would switch tongues, so to speak. His classes were mostly electives, and very tough, but always full.
They didn’t offer Italian at the school, which was my son’s first choice, so he advised him to take French, master it and then pick up Italian the way he did. He actually spent time in Italy to do it, but he said you could really do it locally, if you put in the effort.