Indexing a multilingual site without changing the URL?

Question

Internationalization and localization

Good evening. I wonder if it is possible to qualitatively give the site to the bots for indexing, if the language is changed by the link in the form /change/ru, which, in turn, simply remembers the language in the cookies and gives the rest of the pages based on the cookies. Those. url for en and ru versions does not actually change.
Or should URLs be /ru/... and /en/.... for correct indexing?

Answer 1

If indexing of both versions of localizations is not important - to determine search bots by UserAgent and give the corresponding content.
If you need indexing of both versions, then it will be easier with urls like /en.
Although, in principle, nothing prevents you from making a vinaigrette, just a little more hassle:
- determine "live" users, their language, write / store in session + cookies (you can still in a constant), overwrite the language switch button (don't forget - give a "clean » a link to a specific page with a specific language version will not work, only with a get-parameter in the url);
- define "bots", for bots have something.com and something.com/en (the main hassle - decide whether you need to have a double) + do not forget about tags:

<link rel="alternate" hreflang="x-default" href="http://something.com/">
<link rel="alternate" hreflang="en" href="http://something.com/en" />

You can also indicate multilingualism in the site map. In general, see Yandex/Google docs on multilingual sites.
Something like this)