Y Treigladur: A Checklist of Welsh Mutations

Lewis, D. Geraint: - D Geraint Lewis grew up in Ynysybwl in south Wales, went to school in Pontypridd and university in Aberystwyth. A librarian by profession, he is a prolific author who has compiled dictionaries and written other popular non-fiction books such as 'Lewisiana' (2005) and 'Geiriau Gorfoledd a Galar' (2015). He won the Tir na n-Og Award for the best children's book of the year (excluding fiction) for 'Geiriadur Gomer i'r Ifanc' (1995).