You know, the words that sound like what they are? My kids are shining examples of onomatopoeia use. OK, maybe not perfect examples, but they do make stereotypical sounds when engaging in typical childhood activities. When Lacy cries, she says, "boo hoo!" When Rose laughs, she says, " ha ha ha!" When Rose was a baby, she would say "Ga ga goo goo." Seriously. And her "yummy" noises she makes (or made, as a baby) were always, "Yumyumyumyum." I think there are more, but it makes me laugh when I hear them innocently making these noises.