Looks up the #PangoScript for a particular character (as defined by Unicode Standard Annex \#24). No check is made for @ch being a valid Unicode character; if you pass in invalid character, the result is undefined.
Given a script, finds a language tag that is reasonably representative of that script. This will usually be the most widely spoken or used language written in that script: for instance, the sample language for %PANGO_SCRIPT_CYRILLIC is <literal>ru</literal> (Russian), the sample language for %PANGO_SCRIPT_ARABIC is <literal>ar</literal>.