Your business might be based in a specific geographic area, but your website likely hosts visitors from around the world. So what's the best way to serve the right content or page to users in a certain region or with content that has been translated? hreflang.
Google uses the rel="alternate" hreflang="language" attribute to serve the correct language or regional URL in its search results, so it's important (some would argue essential) that you know how it works and implement it correctly on your website.
Website Magazine's recently published "Fundamentals of International SEO" goes into some detail on how to support a global audience and addresses some key fundamentals of internationalizing your digital presence.
Fortunately, if the translation and localization has been done, it's actually really simple to get started and make sure the right content is being delivered to the right user... every time.
The first step is to decide where the language annotations will go. Translated pages can be indicated with an HTML link element in the header, in the HTTP header itself, as well as within the sitemap.
What is most important to remember is that if you have multiple language versions of a URL, each "language page" must identify all other language versions - including itself. For example, an English version of a website that has translated pages for Spanish, French and German must each include the same references to the English, Spanish, French and German translated pages. While it is most common to specify multi-language URLs in teh same domain as a given URL, it is acceptable to use URLs from an entirely different domain.
For websites catering to users in different locations but which use the same language (as in the U.S., Canada, Austrailia and the UK, it's best to provide a generic URL for those geographically unspecified users. In this scenario, the code (using an HTML link tag) would look like this...