Internationalizing a Python 2.6 application via Babel

By default pybabel extract recognizes the following keywords: _, gettext, ngettext, ugettext, ungettext, dgettext, dngettext,N_. Use -k option to add others. N_ is often used for NULL-translations (also called deferred translations).

Update: The -k option can list arguments of function to be put in catalog. So, if you use n_ = ngettext try pybabel extract -k n_:1,2 ....