Hide month in menu bar in OS X

To change the format of the date, you want to go to your "Language and Text" settings. Click on the "Region" tab at the top, then go to the section under "Dates":

Dates section in Language and Texts settings

Click on the "Customize..." button, then you should see a whole drag and drop section where you can change how the date is displayed:

Customize Date


Go to System PreferencesDate & TimeClock and uncheck Show Date.

Screenshot

To change the language used, go to System PreferencesLanguage & RegionAdvanced and set Format Language to the language you want to use.