It also depends on the game. Some games may store language variables in a "resource file" (this is generally the case if the developers expect the game to be translated), others may hard code the langvars. If the former, it's mostly trying to figure out the resource file format, and editing it (somewhat like RCOs (which are PSP resource files)).
However, the latter case is very difficult. If the code isn't encrypted, you can probably search and find the language phrases in the file, and edit them, however, there may be many potential problems (as discussed earlier). Probably the trickiest part is trying to keep the text to the same length (are you aware of hexing?). For example, if something says "Game", you have to somehow keep your translation to 4 characters.
If you need more space, well, you will generally have to disassemble large pieces of code for that, since inserting bytes will generally stuff up all the program's jumps. I'm not sure if there's an automated means of offsetting addresses like that (though there may be some means of dynamically doing so). An alternative could be if you could for the game to use an external reference to the language variable, instead of using it's own hard coded one. Whatever the case, you can see it's not exactly an easy task, and will require lots of knowledge with disassembly.
PSPkiller Wrote:that's given me an idea. how about making a 'Resource Hacker' style program for psp. to edit eboots and stuff. i know nothing about programming though (i am trying to learn c++ though) so someone else would have to do it.
The problem is, the only way that would work is if there's a common format (ie for Windows, the PE format, or RCOs on the PSP etc). Most game developers don't really seem to follow a common format, unfortunately.