Spelling Rules When Adding Suffixes
Level A2 · Sentence Basics
When you add a suffix — -ing, -ed, -er, -est, or -s/-es — the spelling of the word underneath it sometimes has to change to keep the pronunciation predictable. Four separate rules cover this: doubling the final consonant, dropping a silent -e, changing y to i, and using -es instead of -s. Each rule already appears scattered across other topics — Present Continuous, Past Simple, Comparatives & Superlatives, Plural Nouns — this page gathers all four in one place.
Doubling a consonant and dropping a silent -e both apply before a suffix that starts with a vowel (-ing, -ed, -er, -est):
- double the final consonant when a short word ends in one vowel + one consonant and the stress falls on that final syllable: run → running, stop → stopped, big → bigger. Two consonants together don't double (help → helping), and two vowels before the consonant don't double either (rain → raining). Stress decides it for longer verbs too: visit → visiting keeps a single consonant because the stress falls on the first syllable, but prefer → preferred doubles because the stress falls on the final syllable.
- British English also doubles a final -l even when the stress isn't on the last syllable — travel → travelled — while American English usually keeps one l — traveled. This is simply the well-known British/American spelling split, not a separate rule to memorise.
- drop a silent -e when the suffix starts with a vowel: make → making, hope → hoping. Keep the -e when the suffix starts with a consonant: hope → hopeful, use → useful. Also keep the -e after a soft c or g, so the letter keeps its soft sound: notice → noticeable, courage → courageous.
Changing y to i and choosing -es instead of -s follow the same consonant-versus-vowel logic, just for different suffixes:
- change y to i before most suffixes when the y follows a consonant: happy → happier, carry → carried. When the y follows a vowel, nothing changes: play → played. And y never changes before -ing, even after a consonant, because ii would be unpronounceable: carry → carrying, not carriing.
- add -es instead of just -s after a sibilant sound (-s, -ss, -sh, -ch, -x, -z) or after a consonant + y turned into -ies: watch → watches, box → boxes, baby → babies. The full set of plural spelling rules, including irregulars like knife → knives, is in Plural Nouns.
The most common mistakes come from applying the wrong pattern. One is forgetting to double a stressed short vowel + consonant (runing instead of running). Another is keeping a silent -e that should drop (hopeing instead of hoping). A third is dropping an -e that should stay before a consonant suffix (hopful instead of hopeful). A fourth is leaving y unchanged where it should become i (carrys instead of carries, happyer instead of happier). Another frequent error is doubling a consonant that shouldn't double, usually because the stress falls on the wrong syllable. visitted is wrong, since the stress in visit falls on the first syllable, while preferred is correct, since the stress in prefer falls on the final syllable.
To pick the right spelling change, check three things in order. First, what sound the suffix starts with: a vowel suffix like -ing/-ed/-er/-est can trigger doubling or an -e drop, while -s/-es and -ing behave differently around a final y. Second, whether the word ends in a stressed vowel + consonant (doubling) or a silent -e (dropping). Third, whether the word ends in a consonant + y (change to i, except before -ing) or a sibilant sound (-es instead of -s).