ACToolkit v1.3 For Windows & v1.0 For Mac OS X

[DsPet]

Only the Bulletin Board strings are editable (like AC:WW).
As mentioned, the signposts are hard coded (and language dependent)
For example, if you visit a Japanese town (running the Japanese version of the game), you will read the signposts in English. The NPCs will all speak English too.
There are a few customizable things, like the NPC's names and catch phrases. They are in the gamesave too, but with separate versions for each language.
Something interesting to support later on (but not a high priority)
BTW: I haven't tried what happens if an English visitor reads a Japanese Bulletin Board with non-English characters.
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Also worth mentioning: the ACToolkit editor works on gamesaves for the Japanese game.