-hau

• -áu

Originally causative/denominative; from Proto-Brythonic *-haɣjed, from Proto-Celtic *-sagyetor (causative/denominative suffix). Cognate with Old Irish -igidir (Irish -igh, Manx -ee, Scottish Gaelic -ich).

• (North Wales) IPA^(key): /ˈhaɨ̯/
• (South Wales) IPA^(key): /ˈhai̯/
• Rhymes: -aɨ̯

-hau (first-person singular present -haf)

1. creates a verbal noun from an adjectival root

• After roots ending in unvoiced obstruents, this suffix is found in the form -áu, although -hau is more usual after ll.

llac (“loose”) → llacáu (“to loosen”)

iach (“healthy”) → iacháu (“to heal”)

pell (“far”) → pellhau (“to move further away”)

gwell (“better”) → gwellhau, gwelláu (“to improve”)

• -áu is also used after phonemically voiced plosives, which lose their voicing if also phonetically voiced.

gwag (“empty”) → gwacáu (“to empty”)

caniad (“permission, leave”) → caniatáu (“to allow”)

trist (“sad”) → tristáu (“to sadden”)

Devoicing also occurs occasionally elsewhere.

cof (“memory”) → coffáu (“to commemorate”)

cwbl (“whole, complete”) → cwpláu (“to complete”) (also: cwblhau)

• -hau is used after vowels and other consonants.

cryf (“strong”) → cryfhau (“to strengthen”)

tew (“fat”) → tewhau (“to thicken”)

ufudd (“obedient”) → ufuddhau (“to obey”)

ysgafn (“light”) → ysgafnhau (“to lighten”)

• R. J. Thomas, G. A. Bevan, P. J. Donovan, A. Hawke et al., editors (1950–present), “-hau”, in Geiriadur Prifysgol Cymru Online (in Welsh), University of Wales Centre for Advanced Welsh & Celtic Studies