 Kevin Kline begged John Cleese to let Otto speak French, instead of  Italian, when he wants to seduce Jamie Leigh Curtis, since Kline  speaks French. Cleese insisted that it had to be Italian. Kline  started singing "Volare" because he ran out of Italian cheeses and  other Italian phrases that he could ad lib, and was concerned that  the director did not yell cut, since the producers did not own the  rights to "Volare" when the scene was being filmed.