DekuHaze, different languages would make no difference, at the end of the day they are all common characters, if you can type them theres absolutely no reason they can't be filtered.
What do you mean? Swear words aren't universally the same. The 'F-word' in German or Welsh, for example, is not the as the English version. Also, you're not filtering out individual letters, are you? You're filtering groups of them, in a specific order, which make up the word. This in turn leads to problems when talking about perfectly legitimate things, like Scunthorpe.