Censor replacing words with other words, not ***

[demoniavbh]

I don't really know how to use replacement variables in this case...
I shouldn't replace anything but add...shouldn't I?
I don't really know...I'm not much into PHP and codes, I only touch them and change some thigns I think that might work, but I don't really know how it goes...

For example in this case I know that what I want to change has to do with this

PHP Code:

$ah_text = $this->post['message']; 


but I don't know what to do with the code, repeat it again but changing that "message" for "title", adding only some code somewhere...tsk...

I think it's time to start learning PHP so I can know what I'm doing :S