It's more than just dialog and speech. All the UI text needs to be rendered correctly, the menus, etc. Often there's modal dialog boxes on top which obscures pa

It's more than just dialog and speech. All the UI text needs to be rendered correctly, the menus, etc. Often there's modal dialog boxes on top which obscures partial words. And games don't read very well with machine translation, so you'd still have to teach the system to overlay the correct English localization that was hand made. All that might still have been easier than dealing with spaghetti assembly, but then you are faced with the daunting task of getting someone to actually download your executable. Patching a ROM is pretty well established process. Downloading an extra executable just to run a ROM in your native language is much less so.