I had an Uncle take an assignment in Brazil. The entire family took Portuegese lessons except for the youngest boy who wasn't of school age. He ended up being

I had an Uncle take an assignment in Brazil. The entire family took Portuegese lessons except for the youngest boy who wasn't of school age. He ended up being the only one to become fluent. He hung out with the maids watching soap operas and that's how he learned the language almost by osmosis. He had no accent and knew all the slang.