[kupoartist]

I doubt it. Whilst theoretically possible, the chances that someone has specifically created a tool for ripping and replacing specific PS2 audio* / language files for a game are pretty slim, as are the chances that you're going to find the English script just lying around somewhere. Because you can't alter a DVD-Rom, The resulting disk would have to be created and burned by you, and therefore wouldn't work in an off the shelf PS2. It also wouldn't be an appropriate topic for a forum that doesn't endorse piracy, no matter how much of a grey area creating altered backups would be.

All in all, it'd probably be a lot less hassle simply to buy the English version of the game, even if it was possible to put together the kind of patched version you're thinking of. FFX is hardly an expensive game these days, and it would be quite easy and not too expensive to buy a UK version of the game (this will AFAIK work in any European PS2)

* I'm assuming you want English voices, or that there are in fact German voices in the game. I'm not sure how Square-Enix localised the game, whether they did full German voice casting or simply subtitled the English voices. Either way, the English voices are actually pretty horrid anyway