[eluser]JasonS[/eluser]
To write applications in CodeIgniter you need to use PHP. If you do not know PHP you cannot write applications with codeIgniter. CodeIgniter allows you to focus on the meat of your application instead of fluff. It provides structure, flexibility and hell it speeds everything up. However it is written with PHP and thus PHP knowledge is essential.
You also need to pick up SQL as well.
I would suggest that you build a blog application with php. You can then pick up CI and convert your blogging app. This will give you a good base knowledge to go on to do bigger and better things.
