Hreflang - Supported language values

Use hreflang for language and regional URLs

The value of the hreflang attribute identifies the language (in ISO 639-1 format) and optionally the region (in ISO 3166-1 Alpha 2 format) of an alternate URL. For example:

de: German content, independent of region
en-GB: English content, for GB users
de-ES: German content, for users in Spain

<link rel=alternate hreflang=x-default href=http://www.example.com/ /><link rel=alternate hreflang=en-gb href=http://en-gb.example.com/page.html /><link rel=alternate hreflang=en-us href=http://en-us.example.com/page.html /><link rel=alternate hreflang=en href=http://en.example.com/page.html /><link rel=alternate hreflang=de href=http://de.example.com/seite.html />