How do i mix region / localisation like with Windows ?

[Martin_Kirk]

I'm admin on our JIRA Cloud solution and want to localize JIRA correctly.. 

We all prefer to see the English translation for labels which makes it easier to search for help online. (plus, the danish translations are generally horrible) 

We face problems with the localisation of Dates and Date-pickers though. 

These are presented in US format eg: 01/01/19

and for the datepicker, Sunday is the starting day. 

I've changed the default date-format in "Look and feel" but can't see where these formatting settings are actually used... 

is it possible to mix localisation settings ?