Well, I can only answer about Greeks, even though I think the same answer would apply for other non-English speakers.

I know that many people in Greece are familiar with D&D and that only a few know about Pathfinder (I stumbled upon it randomly on the internet for instance). The Core books for 3.5 had a translation in Greek...actually, I think the translation was for the 3.0, and not for the 3.5 version. Not all people though prefer reading translated material. Most Greeks (with a few simple calculations I would assume around 80% - 90% of Greeks) speak English well enough to understand what's written the books.

Now...since not all people prefer translated material, and since only a few core books (not Pathfinder, D&D) are translated in Greek, I would say that it would be mostly confusing. In my opinion it wouldn't only be confusing, but annoying as well. "Annoying" in a sense that it would look/sound/feel ugly and unoriginal.