What games will Nintendo Switch have?
All types like other Nintendo devises
Most Nintendo DS games start off in their original language and are then either translated and marketed officially by Nintendo, or hacked and subbed by bilingual fans. Although the Nintendo DS itself has a switch-language function, the games you play on it would need to be purchased from a Japanese vendor, imported, or fansubbed for you to get them in Japanese.
Depending if the Wii U doesn't bring as many people as Nintendo hopes. If a lot of people switch to the Wii U and buy less Wii games, Nintendo will see that and then Start their process on switching to only Wii U games. It all has to do with profit and since Wii U games are in HD then more money is better for the company.