According to Famitsu, SKULLGIRLS 2nd Encore is to be published in Japan on PS4 and PS Vita by Arc System Works.
This will include a full Japanese-language dub (although they're probably going to have to come up with their own puns to replace the ones that only work in English). So far, the only voice actor confirmed to be participating is Ayana Taketatsu (probably best known as Azusa from K-on!) as Filia.
This, whenever they get around to releasing it, will be the official website of the game in Japan.