I can’t add the language switcher in the menus
https://wordpress.org/support/topic/i-cant-add-the-language-switcher-in-the-menus/

Fix Suggestion for WordPress 6.6.1 – Language Switch missing in Edit Page
https://wordpress.org/support/topic/fix-suggestion-for-wordpress-6-6-1-language-switch-missing-in-edit-page/

Language Switcher problem with last update
https://wordpress.org/support/topic/language-switcher-problem-with-last-update/