Not exactly, though that is an excellent example of word play. The kind of skill I am talking about would be more like this:
One day we were on a road trip involving many hills, which our toddler enjoyed greatly, yelling (endlessly!) "whee" every time we went down a decline, and "ew" every time we went up an incline (there were many, many hills). This is an example of one kind of higher-level phonological processing skill, namely phoneme manipulation. (Specifically, phoneme reversal.) The DC understood that going up was the reverse of going down, and, analogously, reversed the phonemes of "whee" (/w/- /ee/) to make "ew" (/ee/ - /w/).
Other forms of phoneme manipulation include reversing longer sequences of phonemes (stop -> pots, ball -> lob), elision, or deleting a phoneme (crash -> cash, act -> at), substitution (bread -> broad, crash -> clash).
Here's a good lay resource on phonological awareness, including some activities you can try:
http://www.readingrockets.org/reading-topics/phonemic-awarenessAnd a chart listing the approximate ages at which children typically develop various phonological awareness skills:
http://www.readingrockets.org/article/development-phonological-skills
