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

Here is regex to match all alphabetical letters across international word systems using Unicode property escapes:

Check language support for Unicode property escapes, may not be available in older versions, especially web browsers (JavaScript)

TEST STRING

!"£$%^&*()_+[]{}'#;@~,./¬``
0123465789
àáâasdäæãåāăąçćčđďèéêëēėęěğǵḧîïíīįìłḿñńǹňôöòóœøōõőṕŕřßśšdsşșťțûüùúūǘůűųẃẍÿýžźż
山人口刀木日月女子馬鳥目水
私金魚煙草莨東京
わたしきんぎょたばことうきょう
ワタシキンギョタバコトウキョウ
קרשתאבגדהוזחטיכ
abcdefghijklmonpqrstuvwxyz
ABCDEFGHIJKLMNOPQRSTUVWXYZ
©▓±■╣║¢¥

PCRE (PHP) / GoLang - https://regex101.com/r/iRTxw4/2

Match Letters Only: \p{L}+

Match Numbers Only: \p{N}+

Match Letters & Numbers: \p{N}+|\p{L}+

Match None Letters & Numbers: [^\p{L}\p{N}]

ECMAScript (JavaScript)

Still figuring this out...