I've been looking all over the place for a way to truly localize date output, but without success.
There are posts advising to look for !long-month-name in interface translation, but I don't find this there. Another one was to actually patch the listings in the date_api.module, but it's a multilingual site and I don't want one language's terms hardcoded like that.
I have only very basic knowledge of php, but looking through the date_api.module, it seems to suggest that translations can be pulled from somewhere, but again, I can't find where from. Translating variables only offers some basic ones (slogan etc), not including dates.

I'll be very grateful if someone can shed light on this.