Gohebiaeth, 1990-1995, yn ymwneud ag achos i ddadgategoreiddio Ysgol Casmael, Sir Benfro, o fod yng nghategori A yn ieithyddol, sef rhoi blaenoriaeth i'r Gymraeg, i fod yn gategori B, sef i roi blaenoriaeth i'r Saesneg. = Correspondence, 1990-1995, relating to the case of decategorising Puncheston School, Pembrokeshire, from being a category A school, where linguistically Welsh was given prominence, to a category B school, which would give prominence to English.