It should be possible to enter time values in the interface language. In German for example I want to be able to enter "20. Jahrhundert" and have it recognized by the UI.
|mediawiki/extensions/Wikibase : master||Add DateFormatParser and MwDateFormatParserFactory|
|mediawiki/extensions/Wikibase : master||Don't assume English in MwTimeIsoParser|
|mediawiki/extensions/Wikibase : master||Remove broken unlocalization from MwTimeIsoFormatter|
|Open||None||T87764 Bugs related to time datatype (tracking)|
|Resolved||hoo||T127820 Use localiezd data format when showing TimeValues on the client|
|Resolved||hoo||T95532 [Story] allow localized input of time values|
Both the MwTimeIsoFormatter and the MWTimeIsoParser are still formatting/parsing these messages in English and English only. We made the messages translatable but the localized messages are currently not used, at least not in the repo view and editors.
Note that this ticket should be split into two: