Welsh numbers (edit)
[a], [b] ←  10 [a], [b], [c] ←  19 20 21  → [a], [b] 30  → [a], [b], [c]
2[a], [b]
    Cardinal (vigesimal): ugain
    Cardinal (decimal): dau ddeg, (optionally before a nasal or vowel) dau ddeng
    Ordinal: ugeinfed
    Ordinal abbreviation: 20fed
Welsh Wikipedia article on 20


From Old Welsh uceint, from Proto-Brythonic *ʉgėnt, from Proto-Celtic *wikantī, from Proto-Indo-European *h₁wih₁ḱm̥t, from *dwi(h₁)dḱm̥ti (two-ten).

Compare Latin vīgintī; also Cornish ugens, Breton ugent, Old Irish fiche.


Usage notesEdit

  • Despite being written as u, the initial vowel here is /ɪ/ in north Wales.



  1. (cardinal number, vigesimal) twenty
    Synonym: dau ddeg

Usage notesEdit

Numerals which employ ugain as their final element, i.e. 21 to 39, use ar (on) to connect it to the preceding element, which causes an aspirate mutation, e.g. un ar hugain (twenty-one), pedwar ar bymtheg ar hugain (thirty-nine). Elsewhere in the language, ar causes a soft rather than aspirate mutation.


ugain m (plural ugeiniau)

  1. twenty
  2. (numeral) score


Welsh mutation
radical soft nasal h-prothesis
ugain unchanged unchanged hugain
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.