How to add additional language to the site?

Hello.
There is a website dz-studio.ru
Need to add a function to change the language somewhere on the top write EN|EN.
But how to implement it? in JS is not too strong...
July 12th 19 at 16:56
1 answer
July 12th 19 at 16:58
Make two copies of the website with different languages
HTML tag select make transition

Find more questions by tags HTMLJavaScript