Is there a way to translate a menu link URI?
When I change it in one language (e.g. http://www.example.com), it is also changed in the other language, where I want a different domain (e.g. http://www.example.de).
Link title and description is working as expected.
It is not possible to translate the menu uri itself. If you want different menu links per language you need to create a unique menu per language, and use block visibility settings to limit each menu block to its respective language.
See this Drupal 8 multilingual hack for a step by step guide: build unique menus per languages
I faced a similar requirement. The best solution I found for myself on Drupal 8.5.x was Translatable menu link uri module. You just need to install and follow the steps mentioned in the module description.
Change the menu-link URL-alias as per the required language
for e.g.
I wanna products page URL in French => /produits and I wanna products page URL in Netherlands => /producten
than first create a menu and place the menu item in it => main menu - products (menu item) /node/1 (menu link) URL-alias:- go to the URL alias and add the alias for French language => select the language French => IN System path "/node/1" => In Alias path "produits" Like wise for the Netherlands site => select the language Dutch => IN System path "/node/1" => In Alias path "/producten"
and the title of the link are being translatable from menus itself only
Note:- Enable this settings located at Configuration => "Content language and translation" enable the menu custom menu link,content,custom block and tick all the all their check boxes specially URL-alias in content.and don't forget to enable the Drupal 8 multilingual modules.
It is not currently possible to have language-specific external links. I created a module that addresses this issue. https://github.com/bbenjamin/Drupal-8---Multilingual-Menu-Links With this module, if users are translating a menu item, they are given the option of adding a language specific external link. If they choose this option, the default Name and Link fields are hidden, and replaced with language-specific fields.
A quite small module we used is Menu Multilingual:
The Menu Multilingual module provides multilingual features for menu blocks, to filter out menu items that do not have translated labels or link to untranslated content.
You have to create a menu link for each language and on the configuration for the menu block you should activate both options:
