She came home from school and she learned something

A second grader came home from school and said to her mother, “Mom, guess what? “We learned how to make babies today.”
The mother, more than a little surprised, tried to keep her cool.

“That’s interesting,” she said. “How do you make babies?”

“It’s simple,” replied the girl. “You just change ‘y’ to ‘i’ and add ‘es’.”

The girl was talking about spelling rules—how to make words plural (like “baby” to “babies”) by changing “y” to “i” and adding “es.”