To change the language of the game you have to change your phone's or computer's default language. But only the menus are translated not what NPCs say. There should be a team that just translates things. There are some things in spanish that are in Graal that just don't make sense such as "Buscar en la base de datos" (Search Player database) which probably could be simplified to "Buscar Jugadores" It is clear they used Google translate for most of it.