Mavericks OSX Update 10.9.1 is out - fixes language problem
See: http://support.apple.com/kb/HT6065
The new update to Mavericks fixes the problem with updates not showing, if the primary system language is not set to English:
Fixes an issue that prevented iLife and iWork apps from updating on non-English systems
It does not mention Aperture - but hopefully this problem has been fixed for Aperture as well with this update.