Several questions to implement multi lingual functionality with Umbraco?

I'm struggling to implement the multilingual functionality in Umbraco CMS version 7.5, currently i see 2 possible solutions:

1- Use only one root path

I think the best package as a complement for this solution is "Vorto", all I have to do is create new data types which extends the vorto data types and I can start edit texts directly on document types.

2- Use multiple root path

The idea is to duplicate the main root path for each language.

-> I followed a lot of tutorials on the web but they all relate on previous versions of Umbraco and the solutions i found seem not working with the current version... Once i duplicate the root path and i associate the language to the root folder, what's the next step ?

I have a few more questions:

1. Do you have a better solution than the 2 on top ?
2. How Umbraco knows the client language ? Does it take the first language in the header "Accept-language" in the HTTP request ?
3. How could i extend the default routing to add the language as the first part, for example: http://ift.tt/2dZLybT....

Thank you by advance !