You may want to set the active language for the current session explicitly. Perhaps a user's language preference is retrieved from another system, for example. You've already been introduced to django.utils.translation.activate(). That applies to the current thread only. To persist the language for the entire session, also modify LANGUAGE_SESSION_KEY in the session:

from django.utils import translation 
user_language = 'fr' 
translation.activate(user_language) 
request.session[translation.LANGUAGE_SESSION_KEY] = user_language 

You would typically want to use both: django.utils.translation.activate() will change the language for this thread, and modifying the session makes this preference persist in future requests.

If you are not using sessions, the language will persist in a cookie, whose name is configured in LANGUAGE_COOKIE_NAME. For example:

from django.utils import translation 
from django import http 
from django.conf...