Reverse of Plural

One of life's little coincidences:

The other evening, I was reading Steven Pinker's book Words and Rules: The Ingredients of Language. Specifically, the passage I read included the following from page 192:

Alan Prince studied a girl who . . . was delighted by her discovery that eats and cats were really eat + -s and cat + -s. She used her new suffix snipper to derive mik (mix), upstair, downstair, clo (clothes), len (lens) sentent (sentence), bok (box), brefek (from brefeks, her word for breakfast), trappy (trapeze), even Santa Claw.

That same evening, my daughter Eva (2 years, 7 months) found one piece of leftover cereal on the floor. It was from some Kix that she had been eating earlier. She said, "That's a dirty Kick," holding up the single piece of cereal. Then she disappeared into the bathroom, and then came back out and said, "I throw the Kick in the potty."