Spelling Rule: One sock, two socks. When there's more than one thing, you usually add an S to make it plural. But with words like BABY that end in Y, you have to change the Y to I and add ES. This is one of 20 songs imbedded in our educational spelling software, Wordy Qwerty, that teaches 2nd to 4th graders how words are built in English. The songs help children remember important spelling rules. You can also purchase and download the songs in iTunes, under the title "JingleSpells: Songs to Spell By".