I want to construct a multi-language site. I have my data stored in a database and I wanted to know if there is a way of me knowing which language the user sees. Imagine having a little flag on top of the page and when tha users presses it, he/she will see the data in english or in german or in greek etc... How can I keep track of the language though? If, for example, tha user selects ENGLISH in index.html, and then browses through the entire site, how can I know in every page, that I must retrieve the english data from my database?
The simplest answer is that you set a language-preference cookie when the user makes a choice. You should also look at the possibilities of content negotiation, that is parsing the browser's language preferences and displaying the content according to the choice of the user.