To create a copy of your menu items in multiple languages, go to Website & Apps > Website Designer and click on the Navigation tab.
Click on Edit icon besides a menu item.
Click on "Create Copy" tickbox to create a copy of the menu, select language for which you're creating the copy and enter the name for the translated menu item.
Click on Save.
Associate menu items
Menu associations are used to keep the user on same page when switching to a different language on the website. Once a menu item is associated with other languages of this menu item, user shall be redirected to the associated menu on switching language.
To associate a menu item, click on Edit icon of the menu item.
Select the appropriate menu item in each language which should load when user selects a language on that page.