regex - Can regular expressions work with different languages?

Question

English, of course, is a no-brainer for regex because that's what it was originally developed in/for:

Can regular expressions understand this character set?

French gets into some accented characters which I'm unsure how to match against - i.e. are è and e both considered word characters by regex?

Les expressions régulières peuvent comprendre ce jeu de caractères?

Japanese doesn't contain what I know as regex word characters to match against.

正規表現は、この文字を理解でき、設定？

Answer 1

Short answer: yes.

More specifically it depends on your regex engine supporting unicode matches (as described here).

Such matches can complicate your regular expressions enormously, so I can recommend reading this unicode regex tutorial (also note that unicode implementations themselves can be quite a mess so you might also benefit from reading Joel Spolsky's article about the inner workings of character sets).