I have seen more than one hundred posts about i18n issues and no solution seems to solve my problem.
I have an app running with Django 1.3.1 and it works Fine at my
First of all, your language settings are wrong.
It should be like:
LANGUAGES = (
('zh', 'China'),
('en', 'English'),
('ja', 'Japanese'),
)
Next, check if the domain in your cookie settings are correct.
I had the same problem and thought Heroku's virtual environment would never support i18n, but finally found out that my 'django-language' value in the session cookie belongs to my local testing server '0.0.0.0:5000'.
After changing the settings, my translations done on the local server worked out of the box.