Add the language to the URL

[j.wasilenko]

I'm using the setting "Add the language to the URL" to add de/ en/ ru/ to the front of the url. This works good as it should.
However how can I remove the language from the default site. So if I have www.example.com/de it becomes just www.example.com (and is in German) and then the other sites stay as www.example.com/en... etc...

[xchs]

I'm not sure but maybe you can use this extension: http://contao.ninja/language-to-url.html