Is it good to have language code in URL of Multilingual websites?

Do you guys think it is good to have language code in multilingual websites?
let's say we have a website in English, Farsi, French ,arabic and etc
we will have urls like:

http://www.mydomain.com/en/english.html
http://www.mydomain.com/fa/فارسی.html
http://www.mydomain.com/fr/français.html
http://www.mydomain.com/ar/العربی.html


Please let me know the advantages and disadvantages of this issue.

thanks,