IMO this is rather not correct explanation. Maybe the whole answer is wrong.By setting a different subdomain for different language. For example, en.abc.com or ru.abc.com
This is not a good idea because there can be hundreds of languages. Further, user may not even know which site to go to in the first place.
It may sound like sth Nowadays we may use some part of domain to indicate a language like google.com google.en nikon.pl nikon.nl and convention is to keep tail sub-domain as language oriented
It seems that such approach maybe even efficient in some cases What do you think ?