register_nav_menu() function is possible to pass the second parameter inside wp l10n function:
register_nav_menu( 'primary', __( 'Primary Menu', 'theme-slug' ) );
but how to localize the menu items?
WordPress Development Stack Exchange is a question and answer site for WordPress developers and administrators. It only takes a minute to sign up.Sign up to join this community
Get a WPML plugin - https://wpml.org/
Seriously, get it - it's the most complete solution for multilingual WP site. You can write your own code to translate menu items, but it is not worth it.