To store multi language content, there is lots of content, should they be stored in the database or file? And what is the basic way to approach this, we have page content, reference tables, page title bars, metadata, etc. So will every table have additional columns for each language? So if there are 50 languages (number will keep growing as this is a woldwide social site, so eventual goal is to have as many languages as possible) then 50 extra columns per table? Or is there a better way?
There is a mixture of dynamic system and user content + static content.
Scalability and performance are important. Being developed in PHP and MySQL.
User will be able to change language on any page from the footer. Language can be either session based or preference based. Not sure what is a better route?