iPhone Word Completion Wacko

I've never seen such weird words as the iPhone dictionary keeps suggesting to me while typing text. I read somewhere that the algorhythms will add new, frequently-used words to the dictionary, but there are words I've used daily for 3 months that still do not pop up, while some really wacko, obscure words do pop up repeatedly. Is there (1) a way to disable this feature or (2) an application that will override it with a better dictionary? I've never had this problem (weird words) with the dictionaries in any other text applications.