Three sounds — /s/, /z/ and /ɪz/ — and the sound before the ending decides which. Children produce all three correctly in speech before anyone teaches them.
Word endings
-s / -es SUFFIX_S_01
Strong rule · High reliability · Very common · Beginner · Reading and spelling
Where Wiggler teaches it: Skill 5: Glued Sounds & Spelling Basics
Cats ends with /s/ and dogs ends with /z/, even though both are spelled with s. Buses adds a whole extra beat.
The plural and third-person ending is /s/ after an unvoiced consonant, /z/ after a voiced consonant or a vowel, and /ɪz/ after s, z, sh, ch, x or ge — where it is spelled -es and adds a syllable.
Voicing assimilation, applied automatically by any native or fluent speaker. The rule does not need to be taught for speech — children get it right without instruction — but it does need to be named for reading, so that a child who decodes dogs as /dɒgs/ is told their instinct was right and the letter is the odd part.
cats, dogs, buses, cups, beds
books, hats, maps, trees, hands, girls, boys, boxes, wishes, matches, glasses, pages
Made-up words that follow the rule. A child who reads these has the pattern rather than the vocabulary.
blats, shugs, frixes
The classroom value here is permission, not instruction. Children already say dogs correctly; tell them so, and point out that this is why they should not write dogz. For the -es cases, clapping the syllables makes the extra beat obvious: cat-cats is one clap to one, bus-bus-es is one to two.
To read with every step of the way.
The reading buddy that listens. Structured, personalised phonics for ages 4 to 10, in joyful minutes a day.
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