Oh, I just did it in Photoshop. I covered up the original text with white rectangles, and then entered the translation in a text box on top, using multiple layer folders to keep things organized. The biggest problem was finding a suitable font (I'm not terribly happy with the one I ended up using, but I haven't seen any good BD handlettering-style fonts out there). I had to make the ellipses specially, since just typing ... or . . . didn't come out right.
The only part of it that took slightly more advanced skills was the "I HEAR YOU FROM SOLUM" special effect caption (which is a near-exact match for the original, if I say so myself).
It took way more time to translate the text than it took to do the lettering (though it would probably have gone quicker if I actually spoke French).