An SEO professional asked John Mueller during a hangout about hreflang tags.
Their situation is: say they have one website that they target in a specific language with that domain, and it also performs well in that language.
Then, they decide to create an English version of the site to target people more globally in a brand-new domain.
They asked if they should add hreflang tags in order to connect the two domains, or should they leave it alone to allow Google to figure it out by themselves?
And, is it possible for hreflang tags to impact their site’s performance?
John answered that hreflang is on a per page basis, not a per domain basis. It would only make sense if you have equivalent pages in other languages for other countries.
It’s not something that impacts the entire website.
If you have pages that have equivalent versions, hreflang tags are a great way to connect them.
Hreflang, however, does not increase rankings. What Google will do is try to swap out the URL against the best fitting one.
So, if someone is searching for your site name, and they have an English version and a French version, then they will be able to show French users searching in French the French version of the homepage.
This works across different subdomains, and is a good practice.
This happens at approximately the 9:45 mark in the video.