utf8

Text by its letters, in any language (a string's own places count bytes).

utf8.len(s)

How many letters a string has, in any language.

utf8.sub(s, from, to?)

The part of a string from one letter to another: like string.sub, but it never cuts a letter in half.

utf8.char(...)

A string of the letters with these numbers.

utf8.codepoint(s, place?)

The number of the letter at a place in a string.