PHP change the website content through language selection

Am doing PHP, MySQL CMS based website for one of my client. Currently we have three languages English, French and Flemish.

For my question is, i am having index.php, about.php and reach_us.php for example. Default the website www.url.com (for eng). Whenever i click the French from dropdown, then the url is changed into www.url.com/fr/. Got it??? Not only for this. When i click http://ift.tt/1BjLGCA, the corresponding page will open. After that i click flemish language, it redirects to http://ift.tt/1GgyMed... Hope you understand what i am asking.

How can i achieve that??? Using PHP or .htaccess and HOW?

Thanks in advance,

Karthik N