As PhutilTranslator::chooseVariant accepts locale codes en_US, en_GB, en_W*, en_R*, en_A* and cs_CZ only.
I expect to move this stuff into Locale subclasses eventually, but it's potentially performance-sensitive so I want to be careful when doing so.
If you're trying to translate into another human language (like French or Spanish or Italian), I'll accept new PhutilLocale subclasses into libphutil (with corresponding rules in PhutilTranslator) if you want to send a diff.
If you're trying to translate into a specialized English, you'll have to patch locally or wait for the rules to move into Locale classes.
Add a new Locale file here:
Then implement gender and plural rules here: