This comes from a conversation on Miiverse...

Marty (NoE, Miiverse operator): Actually, I do have a question! What about Japanese songs? If I remember correctly, there was talk about Japanese songs in the Nintendo Direct...

Ella (NoE, Wii Karaoke U): I'm sorry to keep you all waiting. I believe we will be able to deliver good news to you in the near future...

Marty: All right, I'll be looking forward to that. What about songs in other languages, like French, Italian, German...?

Ella: Well, I know some people have been making requests for songs like that in this community too. I will do my best to make sure those things happen some day.

Source: Miiverse