I have installed following modules :
6.Content type translation 7.Menu translation
I added Arabic language .po file using admin/build/translate/import. I added one menu item for English and another menu item for Arabic in primary links. The menu items added for English are displayed on a node view page (when English is selected from language switcher) but the menu items added for Arabic are not displayed on a node view page (when Arabic is selected from language switcher).