First, learn about the "regexp" feature. Perhaps start with perlretut. For example, /\d+/ will match a sequence of digits (0 through 9). Similarly, you can find a sequence of characters that are used in Asian languages, as opposed to ASCII or other Latin, Greek, etc. characters.

There are built-in classifications, including "Han", which another poster illustrated.

So, use a pattern that finds all occurrences of Han characters within your mixed text.