If you create a ticket in a topic that require statutory declarations, you'll see Statutory declaration field description in English. The same applied for Ticket xx was created message. However, in shell everything works.
>>> from django.utils import translation
>>> from django.utils.translation import ugettext_lazy as _
>>> translation.activate('cs')
>>> _('English')
'angličtina'
>>> _('Statutory declaration')
'Čestné prohlášení'
>>> _('Ticket %s is created') % 'a'
'Vytvořen tiket a.'
>>>