ocStore how to set language from uri (verion 2.1)

The problem i faced and didn’t find any solution in internet.
But a lot of questions around it on many resources.
Even the corresponded thread in official ocStroe blog was without answer. (the last answer in this thread is mine now)

So be stright. The solution not so complicated and almost all changes we have to do in index.php and few files more

For the beginning let’s just have a look to the .htacces file to understand how the engine work with the requests