dau ddeng

Welsh

**Welsh numbers ^(edit)**
		200
^{[a], [b]} ← 10	^{[a], [b], [c]} ← 19	20	21 → ^{[a], [b]}	30 → ^{[a], [b], [c]}
		2^{[a], [b]}
Cardinal (decimal): dau ddeg, (optionally before a nasal or vowel) dau ddeng Cardinal (vigesimal): ugain Ordinal: ugeinfed Ordinal abbreviation: 20fed
Welsh Wikipedia article on 20

Literally, “two tens”.

Used before blynedd, blwydd, nouns beginning with m or n, and optionally before diwrnod and nouns beginning with a vowel. Triggers nasal mutation of b and d.^[1]
dau ddeng mlynedd ― twenty years
dau ddeng mlwydd ― twenty years old
dau ddeng milltir ― twenty miles

Mutated forms of *dau ddeng*
radical	soft	nasal	aspirate
dau ddeng	ddau ddeng	nau ddeng	unchanged

Note: Certain mutated forms of some words can never occur in standard Welsh.
All possible mutated forms are displayed for convenience.

^ Thorne, David A. (1993) A Comprehensive Welsh Grammar (Reference Grammars), Oxford and Cambridge, MA: Blackwell, →ISBN, § 202 n. 2, page 147