Get script/language for fonts via terminal
fc-scan

You can use the command line tool fc-scan to list the properties of a font, including supported languages. The languages are reported under lang: as ISO two-letter country codes:

fc-scan /Library/Fonts/Arial\ Unicode.ttf


fc-scan is part of fontconfig, which is available through the brew project using:

brew install fontconfig


See also Mac Terminal: Get list of Chinese fonts from a given folder