What do the foxes say in Sing?
What Buster Moon said in Japanese to the five Japanese red pandas roughly translated to "Your routine is horrible, your footwork stinks like feet." It's possible he may have wanted to say that "You are in my show, sleep well and start fresh tomorrow."
What is the purpose of what does the fox say?
1) The original song was an advertisement for a Norwegian talk show. The Ylvisåker brothers are a comedy duo from Norway, and the original idea for creating the track and the video was simply to promote the brothers' third season of their talk show, I Kveld Med Ylvis (Tonight With Ylvis).