Feature summary:
I would like to use {{TRANSLATIONLANGUAGE}} in templates, so the template work both inside and outside translation units.
Outside translation units, it should return the same value than {{PAGELANGUAGE}}
Use case(s):
meta:Template:DateT displays a translated date in page language. If we use it inside a translation unit, that creates language inconsistency while the unit is not translated yet (date in translated language, remaining unit text in source language).
Benefits:
The {{TRANSLATIONLANGUAGE}} would work everywhere, the text language would remain consistent with explicit HTML lang attribute keeping the page accessible for screen readers.