The y to i rule

When does the rule apply?

The letter before the y decides everything. After a consonant, y is acting as a vowel, and it turns into i when a suffix is added. After a vowel, y is part of a vowel team (ay, ey, oy) and stays put. The -ing exception has a practical reason: "criing" would put two i's side by side, and English avoids that. Our tables split the changed words by suffix, because students meet -ies and -ied first and -ier, -iest, -ily and -iness later.

Words that follow the rule

Words that break the rule

How do you teach it?

Teach the plural and past forms first, since students see them most. Write "baby" and ask the class to spell "babies". Then put "monkey" next to it and ask why monkeys keeps its y. Let students find the difference themselves: a consonant before the y in baby, a vowel before the y in monkey.

"Our word is 'carry' and we're adding -ed. What letter comes before the y? r, a consonant. Is the suffix -ing? No. So the y changes to i: c-a-r-r-i-e-d. Now 'carrying'. The suffix is -ing, so the y stays, or we'd get two i's in a row."

What is the common error, and the fix?

Students write "babys", "cryed" and "happyness" when they skip the rule, and "plaied" or "criing" when they overapply it. The fix is two checks in order. What letter comes before the y? Is the suffix -ing?

Sort it: a hands-on activity

Make three columns: "change to i", "keep y: -ing" and "keep y: vowel before". Students draw base-plus-suffix cards (spy + es, enjoy + ed, fly + ing, lucky + ly, key + s), sort them and write each new word.

How this list was built