I have a website which has 25 different language versions on 16 different domains. Hreflan are setup to point to different language versions.
In the footer we have deeplinks to the 25 language versions. Site is not spammy but in small niche and many language versions have very few other external links. For some time this site had lost rankings for reasons that are unclear till now.
I see that large international sites such as booking.com, tripadvisor, apple all use different approaches to interlink their language versions. Interestingly Tripadvisor is nowadays loading the links to their other language versions dynamically only upon click so that these links do not show up in source code, deviating from their former implementation of static deeplinks to all language versions.
Matt Cutts mentioned back in 2013 “If you have 50 different sites, I wouldn’t link to all 50 sites down in the footer of your website, because that can start to look pretty spammy to users. Instead you might just link to no more than three or four or five down in the footer, that sort of thing, or have a link to a global page, and the global page can talk about all the different verions and country versions of your website.”
But in their webmaster guidelines google recommends: "Consider cross-linking each language version of a page. That way, a French user who lands on the German version of your page can get to the right language version with a single click."
I assume for SEO anyway these links have no value, but for user experience it would certainly be better to provide somewhere deeplinks to other language versions. Also the fact that language versions are on different domains and have few external backlinks may increase a bit the risk in our case. I guess in doubt I would prefer to be safe and load deeplinks only upon click same as tripadvisor.
Any thoughts/suggestions on best interlinking in our specific case?