What about 2 and 3? And the PS2 games for that matter? I know this doesn't answer your question but I'm playing through Badass Rumble on the PSP right now and I don't think that 2 or 3 are available in English either. Nor are the PS2 games.
But as for your question, I mean it probably is possible? It's just that translating games usually requires a team of translators and modders, people who know how to go through all the game files and mod them without breaking everything. For translators I'm sure you can find some that would take the job, but without modders who can find every bit of text in the game and give it to the translators I don't know what the chances are. I don't know how you'd find those modders willing to do it.