What is the best way to specify the locale in a URL?

Question

Search Engine Optimization

Hello!
What do you think is the best way to specify the locale in a URL?

site.com/en/about
en.site.com/about

Answer 1

The most common locales of this type are site.com/en/aboutfor examplehttps://www.jetbrains.com/ru-ru/

Answer 2

There is a big difference for SEO.
This is one site
site.com/en/about
site.com/ru/about
And these are two DIFFERENT sites for Yandex and Google. Each will have to be promoted separately.
en.site.com/about
en.site.com/about

Answer 3

If we are talking about search engine optimization, then site.com/en/about is preferable to me.
So the site tree will be larger, more semantic core.