Splendid, I'll have it running in my head for days now...

I've got the Welsh version on a tape somewhere, will have to send it in.

Philosophers have only interpreted the world; the point is to change it.

I think the American lyrics are still my favourite.

Ooops. link to lyrics here.

Isn't there a scene in Land and Freedom where a group of Brigadists sing it in various different languages? I always found that very moving and symbolic (though not exactly subtly so) of the unity it describes.

So BtGoG's link was funny in a gallows humour sort of way. There are three different English versions. It's not difficult to imagine a similar scene with a group of socialists from different splinter groups all singing different versions in the same language.