Hello! For good search engine optimization(SEO), it is better that each language version has its own URL, for example mysiteurl/ru

That is correct but 2 problems here:
- too complicated
- for 1% of users

- for 1% of users


I think 100% of users will be happy if their site is indexed well by search engines.
I agree that it is difficult, but you are an experienced programmer.

@alex7070
Even now pages are correctly indexed.
Problem is that most of listings will have title/description in one language only, that means URL in different locales would be same except language code.
Another complication is that Osclass use 5 char format for language, i.e. en_US (then it could be also en_GB).
This is issue as you do not want this code to be in URL.

There would be also negative impact on existing sites as changing URLs is never what you want to do on production website.

As it is now, Google will not index different language versions because they are all located at the same URL.

@alex7070
Yes correct.