[PSX] Problems translating P2: Eternal Punishment

[lummie]

I was trying to translate a game (Persona 2 Eternal Punishment from PS1) into another language (portuguese), but I have a problem:
Some words are "incomplete" in the Hex editor.
Example:
Inside the game the phrase is "Did you lose something important?" and in HxD the phrase is "Did y,!␁se€!␑mething important?".
If I remove these commas and these special characters the game crashes.
Does anyone know what these characters are and how I can translate this game with their presence?

*Sorry for the spelling, I'm using Google Translate to help me

[KingMike]

It is compression. Most likely a form of LZSS.
LZSS (and its variant forms) has enough variation you are not likely to find a generic tool to decompress it.

However, it is a popular game, and Innocent Sin has been fan-translated, which I would imagine to use the same compression since it's another half of the same game, isn't it?
So someone might have more information about the particular game.