Sitcoms are a tried and true language promotion tactic. I remember when I was young there was a French teenage-sitcom, "Helene", which my mother would watch because her students watched it religiously (she was a language teacher). It was outrageously soapy, but even I noticed the relatively accessible language. My mother told me the show was a subsidized export of France's language evangelization program. Apparently teaching French was a lot easier when that show was popular.

Friends wasn't that, but close enough. I think I recall Simone Giertz saying that she learned English from it, and I can't be the only one who has noticed that there's something uncannily Lisa Kudrow-like about her stage persona.