No need to create a menu item for each language. Create items only for one language and use the Translate tab (next to Edit menu link), to translate to the other languages.

More technical:

Select Menus from the Structure menu
Under Operations click the edit menu link
Set translation mode to Translate and Localize. Menu items with language will allow translations. Menu items without language will be localized., under MULTILINGUAL OPTIONS.
Re-enter Menus. This time click the List links link
Click the edit link next to the menu item you want to translate.
Make sure that the Language is set to a value other then Language neutral.
Go to the Translate tab.
Click the add translation link next to language you want to set.
Set Menu link title to a title in your selected language and save.