Author: D. Geraint Lewis.

A new edition of an alphabetical list of Welsh words that cause a mutation, and a summary of the main rules of mutation, together with an explanation of the grammatical terms used. First edition published in 1993.

Awdur: D. Geraint Lewis.

Argraffiad newydd o restr o eiriau Cymraeg sy'n achosi treiglad, a chrynodeb o'u prif reolau, ynghyd ag eglurhad o'r termau gramadegol a ddefnyddir. Cyhoeddwyd yr argraffiad cyntaf ym 1993.