Alternative Hreflang for SEO
This module allows you to customize the language codes used in hreflang attributes for SEO purposes. You can set alternative language codes that differ from the registered language codes in your site's URLs, which is useful for multilingual websites.
Alternative Hreflang for SEO is a Drupal module that allows the language code in hreflang attributes to be customized, without altering the registered language code used in the website's URLs.
The module provides an admin settings form which will list all of the languages enabled on the website. You may provide an alternative language code for any language. While you can set it to the same language code as the language's default language code, it is not necessary to do so, as the hreflang language code will only be overridden if a different code is provided.
Requirements
This module requires no modules outside of Drupal core.
It is only useful for multilingual websites, so you will need to have the core Language module enabled and some content translated into more than one language.
No knowledge of coding is necessary to use this module.
Similar modules
If you do not need to override the language code for the hreflang attribute (or you are comfortable writing your own hook implementation), you may wish to consider Hreflang, or Metatag Hreflang.