Alternate Url's for the different languages

Hi All, I have SEO related question. Is their a nice way to get all the alternative url's for the different languages of a page? I would like to set the different alternate link tags in the head of my page if they are available (for optimal SEO).

--- html
<link rel="alternate" href="http://example.com/de" hreflang="de" />
<link rel="alternate" href="http://example.com/nl" hreflang="nl" />

The simple solution would to be guess the url's by simply prepending the language identifier. But that could create problems if the translation is not available.

In a Twig file try page.translatedLanguages (from the API). It's an array so you need to loop over it.