I dunno about the 8330, but every BB that I remember having you can add words to the custom dictionary.
On OS7 (Sorry, Its all I have in front of me to reference right now...) Hit "Options", then "Typing and Language" and you should see Custom Dictionary in the list. Open it, hit the Blackberry button and you should see an option to add new words.
Add as many words as your heart desires as, as far as I know, you can add an unlimited amount of words.
Something similar has to be implemented for your 8330, the directory might be different though. Try looking for your Custom Dictionary!