Where did this cutesy baby talk come from?

LoLo just turned 4 on March 2nd, and with this birthday I really held out hope that he would become more mature and responsible. Then bam, he starts in with the baby talk! What?! He has decided that it is funny to add little endings to words, such as: "schooley"-for school, "pickie"-for pickle.  I know that he is just doing this to be funny and get attention, but after awhile it just became annoying and I felt like others were thinking he wasn't as smart as he really is.  I talked to him about it, yet he still is doing it so I decided to try and go with it for now.  I realize that there is a positive side to this issue as well, and I am trying to remind myself of that every time he does it.  The positive side: as he begins to experiment with changing words (like adding 'ie' to the end of words) it shows me that he is starting to understand that words can be changed and still retain their base meaning.  This skill is a very advanced concept for young kids, and shows that they are starting to realize that words are made up of parts (onsets and rimes, base words, suffixes and prefixes, etc.).  Eventhough his understanding is very primitave, it is still there....and this is what I am going to tell myself everytime he says 'cutie-wootie!' Ugh!

I want to know what your little ones are saying? Any cute baby talk that is driving you nuts? Don't forget to include your child's age.