In the last years, Square Enix has localized major games like Hitman, Tomb Raider and Deus Ex for multiple markets, including voice tracks in languages like French, German, Italian, Spanish or Portuguese. While English and Japanese voice casts have been shared for Final Fantasy XV already, Square Enix so far remained silent on whether more languages will be supported with dubbing voices or not.
During an interview with NovaCrystallis.com, Hajime Tabata, the game's Director confirmed that Final Fantasy XV will ship with Japanese or English voices only.
More dubbin voices are possible as a DLC later or when the game comes to other systems.
Tabata also mentioned that they plan to support more text-translations of the game, including more countries to reach new players.