Ace Attorney 5 will be the first game in the series to feature voice acting, according to an interview developer Takeshi Yamakai did with Nintendo Dream magazine (in Japanese).
Prior to Ace Attorney 5, the Ace Attorney games only featured voice acting in the trailers. In the series' latest installment, voice acting with do away with the "bleep-bloops" that accompanied character dialogue, which the developers acknowledge will be met with much resistance from the game's fans.
Yamakai explains in the interview that the voice acting was introduced because of the NIntendo 3DS' surround sound capabilities, which would have made porting DS sounds to the newer console difficult by creating tuning problems. The developer also said the team wanted the game to flow into the anime-esque cutscenes, which are fully voiced.
Ace Attorney 5 is set for a 2013 release on the 3DS.