The next game in the Professor Layton series is currently being worked on, according to Level 5 CEO Akihiro Hino.

Level 5 is currently working on the crossover title Professor Layton vs. Ace Attorney, but it seems they are also cooking up the next game in the Layton series.

"The general framework for the next Layton title has been outlined," Hino said. He also added that there would be a bit of time before they could announce anything officially.

Hino did give away one little spoiler about the game: it will have a long title in Japanese. 

It can be assumed that whatever this game is, it will eventually make its way to both North America and Europe. However, seeing how the previous entry in the Layton series, Professor Layton and the Mask of Miracle, has yet to see release outside of Japan, it can be assumed anyone not in Japan will have to wait quite a while for this next game.