While a website is nothing more than a collection of words and images, how you present and serve that collection to your visitors is wide open. You will need to output your collection in HTML (Hypertext Mark-Up Language), as that is what is understood by browsers. You should also be mindful of website accessibility rules and regulations that you may need to comply with (depending on your industry). Here are some places to start learning about the languages of the web.
HTML

CSS

JavaScript

DHTML

PHP

MySQL

Ruby on Rails

ASP

ColdFusion

Java