Plurals by Vowel Change
Like English man → men, some Welsh plurals change a vowel: car → ceir, tŷ → tai, ci → cŵn.
How It Works
Vowel change only.
- car → ceir (cars)
- bachgen → bechgyn (boys)
- dafad → defaid (sheep)
- tŷ → tai (houses)
- ci → cŵn (dogs)
- carreg → cerrig (stones)
- castell → cestyll (castles)
- troed → traed (feet)
- asgwrn → esgyrn (bones)
- maneg → menig (gloves)
Vowel change plus an ending.
- gardd → gerddi (gardens)
- mab → meibion (sons)
- gair → geiriau (words)
- cadair → cadeiriau (chairs)
A common pattern. An a in the singular often becomes e or ei in the plural (dafad → defaid, car → ceir). This is a tendency, not a rule. Most nouns use plural endings instead.
Mutations work as usual. Plurals never soften after y: y bechgyn, y defaid. After fy they take nasal mutation like any noun: fy nhraed i (my feet).
After a number you normally use the singular, not these plurals: dau gar, pedwar ci. See nouns after numbers.
Examples (6)
- Mae'r bechgyn yn chwarae pêl-droed.
The boys are playing football.
Bachgen (boy) becomes bechgyn.
- Mae'r defaid yn y cae.
The sheep are in the field.
Dafad (one sheep) becomes defaid. Like all plurals, defaid does not change after y.
- Mae'r cŵn yn cyfarth.
The dogs are barking.
- Mae'r tai yn y pentref yn hen.
The houses in the village are old.
- Mae fy nhraed i'n oer.
My feet are cold.
Troed becomes traed, and fy turns t into nh.
- Mae gormod o geir ar y ffordd heddiw.
There are too many cars on the road today.
Ceir softens to geir after o.
Common Mistakes
Adding a regular ending to a vowel-change noun.
Mae'r ciod yn cyfarth.Mae'r cŵn yn cyfarth.Ci does not add an ending. Its plural is cŵn, with a new vowel.
How It Connects
Learn This First
Vowel-change plurals extend plural formation.
Related Patterns
- Nouns After Numbers Stay Singular
After numbers, use the singular instead.
Level 1 - Singulatives -yn / -enSingulatives: -yn and -en
Another kind of singular and plural pair.
Level 4 - y + Feminine NounSoft Mutation After Y with Feminine Nouns
Plurals never soften after y.
Level 1 - fy + Nasal MutationMy: Fy + Nasal Mutation
Explains fy nhraed i.
Level 2
Learn Next
Patterns that build on this one.
Practice Plurals by Vowel Change in Bubblegum
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