How to match the international alphabet (English a-z, + non English) with a regular expression?

Question

I want to allow only entered data from the English alphabet and from the alphabet from Germany.

Like öäü OR France like áê or Chinese like

Answer 1

It varies. Some languages have a "Unicode" flag which extend \d, \w, etc. Some support equivalence classes in a range, e.g. [[=e=]] matches e, é, ê, etc. The regex documentation for your language or library will explain what options are available.