PHP alpha-numeric characters and underscores (A-z, 0-9, and _ )

Question

If PHP can only have alpha-numeric characters and underscores (A-z, 0-9, and _ ) in its titles, how do people with different alphabets code PHP?

Answer 1

Possibly they have to use the Roman alphabet (which is the one used in languages such as English, as far as I know). In any case, if they are web developers they should already be familiar, since w3 organization states that all HTML tags should be written in English, and not in another language.

https://www.w3.org/International/questions/qa-non-eng-tags