Consider Number of Language Variations When Deciding on Approach to Internationalization
Consider the number of language variations when deciding how to configure international versions of a website. If there are many versions you may want to let the user decide which version they want to view, but if there are only a few versions you may be able to guess for them.
Make Pages Accessible to Googlebot For Each Language Version of a Page
For sites with redirects based on the user’s IP or browser language, John recommends having landing pages available for each individual language, including hreflang on each with an x-default to the main page.
Use Hreflang & Canonical Tags to Handle Partially Translated Websites
John recommends using canonical tags and hreflang tags to tell Google which language version is preferred if you only have parts of a website that are translated, instead of the entire site.
Same Language Country Versions Can Cause Problems With Location-specific Information in SERPs
Google swapping out URLs for same language country versions of a page can be problematic when the title or structured data shown in the SERPs includes location-specific information, such as pricing. E.g. a Swiss searcher sees the Swiss URL but German pricing in Euros.
Google Folds Together Same Language Country Versions & Swaps Out URLs Dependent on Searcher Location
Google identifies different country versions of the same language as duplicates and folds them together for indexing. Google can then swap out the URLs depending on where the search is performed.
Google May Include Translate Link in Search Results for Pages with Multiple Languages
If multiple languages are included on one page, Google may include a ‘translate this page’ link in the search results if it can’t determine the primary language of the page.
Partially Translated Pages May Rank if They Are the Best Matched Version
Google tries to show the best matched version of a page for users in the language and region that they’re searching for, even if that version is only partially translated.
Google Can Understand Pages Featuring Multiple Languages
Google can understand pages that contain multiple languages. For example, a travel site about Spanish cities might be in English but feature Spanish place names.
Google Requires Multilingual Sites to Have Some Form of URL Differentiation
Anything that differentiates a URL can work for Google for multilingual sites with hreflang e.g. subdomains, subdirectories or parameters.