Comment 6 for bug 560591

It seems that the issue here is that Software Center only works as expected when using the LANGUAGE variable

Some tests, running in a non-English locale [1]:

$ LC_ALL=C software-center
$ LANG=C software-center

Expected: Software Center runs in the default POSIX locale (US English)
Result: The menus are in English, the UI is in the user's locale

$ LANGUAGE=en software-center

Expected: Software Center runs in the default POSIX locale (US English)
Result: as expected, the whole application runs in English

[1] Here's my current locale:

LANG=ca_ES.utf8
LANGUAGE=ca_ES:ca:en_GB:en
LC_CTYPE="ca_ES.utf8"
LC_NUMERIC="ca_ES.utf8"
LC_TIME="ca_ES.utf8"
LC_COLLATE="ca_ES.utf8"
LC_MONETARY="ca_ES.utf8"
LC_MESSAGES="ca_ES.utf8"
LC_PAPER="ca_ES.utf8"
LC_NAME="ca_ES.utf8"
LC_ADDRESS="ca_ES.utf8"
LC_TELEPHONE="ca_ES.utf8"
LC_MEASUREMENT="ca_ES.utf8"
LC_IDENTIFICATION="ca_ES.utf8"
LC_ALL=