Using International IP Redirects Will Prevent Google From Finding Other Versions of A Site
If you are redirecting based on international IP addresses, Google is likely to only see the redirect to the English version and would drop all of the other versions.
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.
Translating Core Pages Can Help Google Understand a Language Change
If a website wants to target a particular language to appear for in search, translating core pages that are internally linked the most, like the homepage, can help Google to understand the language change. However, this doesn’t guarantee improved rankings for the target language.
Googlebot Does Crawl From a Handful of Regional IPs
Googlebot does crawl from a small number of regional IPs, particularly in countries where they know it is hard to crawl from the US.
Google Can Process Hreflang Tags Regardless of How They’re Implemented
It doesn’t matter to Google whether you implement hreflang tags in the HTML, in the HTTP header, in an XML sitemap or through a combination of these methods. Google will process the information in these tags regardless of the implementation method.
There Are No SEO Benefits For Translated URLs
As long as Google is able to see unique URLs for each language, it is not a requirement for each word within the URL to be translated. While it can be positive for user experience, it doesn’t provide any SEO benefits.
Google Is OK with Domains Served from Different IP Addresses
Google is fine if domains aren’t always reachable from the same IP address. This is common with many sites that use CDNs where users from different locations are being dynamically allocated to different servers.
International Websites on Separate Subdomains Will Not Be Penalized for Duplicate Content
Google will not penalize international websites that exist on separate subdomains if they have duplicate content. Instead, it will recognise the pages are identical and in most cases index both, but will only pick one URL to show in search results.