I don't know if anybody has delved into the font handling of this game such that they could give you an answer, much less them being on this site (we happily hack PSP game and host discussions but compared to the likes of the GBA, DS, 3ds and so forth there are far fewer knocking around).
Still character placement is usually handled by either the game's code or the font format itself (some massive table usually at the start or end of the font, but I have seen it character by character) where it details width and height, and in some more advanced cases then also line height (for English/Roman characters think yjgpq) and that might also be happening here.
Alternatively that might be a fixed width game -- normally I would expect to see characters like i, l possibly j and maybe f squashed up against other characters (like you might well be reading this here). In which case you would probably have to add it yourself (which is going to involve code unless the devs had it but did not use it, which is rare). Mind you the Cyrillic letters there are very different spacing -- when you say replaced how did you do it? If you took a file from another game using the same format which does have Cyrillic support or a premade font some other hacker made then I would have to wonder if the font itself has some measure of spacing support. In that case you are back to figuring out where in the font the spacing is made, or overwriting the Roman characters in the original font with Cyrillic (or adding the extras of whatever vintage Cyrillic you care about has over what the Roman one provides).