Comment 8 for bug 655427

@trespasser
I can't tell why Language Support asks you to install the Polish language packs. Maybe you should just install them for now to make your computer happy. ;-)

The language used for weekdays and months is derived from the locale you selected for date format, i.e. Polish in your case. To change date format only, but keep such as currency and number format in Polish, you can edit your ~/.profile file manually and add this line:

export LC_TIME="en_GB.utf8"

@trespasser and Ghosty
When you select different locales for message translation and other localization aspects, Ubuntu mixes them up sometimes. I'm working on a patch that will fix that; see bug 553162. It's conveniently available for testing at https://launchpad.net/~gunnarhj/+archive/locale-test

It would be great if you could test the patch and let us know about your observations.

I'm marking this bug report as a duplicate of bug 553162, since they in effect address the same issue.