Something confusing about the Date translations

[Clubnite]

There is something unclear about the date topic. I am working on a calendar and using the JDate class to get the required parameters. But i wonder how i would ever reach the translations from the global site translation ini file. In there i found all month and weekday name keys to be in uppercase english. Thats clear. There are also shorts which is what i need as well. But everytime i select a site language from the backend config the month names are getting translated so the english keys in the de-DE.ini are useless this way.

When working with the date class:

Would i have to add german keys there to getting enabled to reach the keys?

How to reach the shorts which i need for the day name headers?

regards,

clubnite