Note: 

• On multi-language sites, for the language selector to work correctly, each language sites should have the same site structure with the same page name. For example, if there is an en/about-us.html page on the English site, there should be following pages under Arabic and Portuguese sites too respectively: ar/about-us.html and pt/about-us.html.
• If there is no page with same name on other language site, on clicking the language selector, the user will be redirected to the parent page of the current page in that language.
• If there is no requirement to create the about-us page in other languages, those page(s) should still be created and then set to redirect (via page properties) to the homepage of the site.