Developers have no set way to depict text within their games and the "obvious" ways if you are a programmer (you want something which does not strain the system too much, and it is not like people will need to change it once it is made) make the ability for end users to simple edit it far from what they might consider easy.
To that end unless someone else has programmed a tool for that game or you have got lucky and found a simple text game (they have happened, PC sometimes and something like Zombi Daisuki on the DS if you want a console example*). There might be some games out there with similar text formats such that a tool could be made for them but I don't know if there are many such games, much less untranslated ones if you are going for English, using such a format for the 3ds (on the DS there was a format but it was pretty much only Nintendo that used it).
*still not done either for that matter.