Here is a recent example. I was working with the two kindergarteners and we were reading a Starfall reader. (There stuff is fabulous! AND so much of it is available for free online! www.starfall.com)
Anyhow. One of the kiddos was decoding the words and on this page, changed one of the vowels.
The last word on this line has a short a sound. Student changed it to short u. While true, it changes the entire meaning of the sentence.
* For those of you unsure of what it said, it would read, "The tin man has a butt."
Yes, I laughed.