Verb-Noun Stems Rules for Regular Stems 1. Verb-Nouns that end in a vowel drop their final vowel, e.g.: talu = tal- pay codi = cod- rise, raise ffonio = ffoni- phone 2. VNs ending in -au change to -eu-, e.g.: dechrau = dechreu- begin 3. VNs ending in a consonent usually stay the same, e.g.: eistedd = eistedd- sit symud = symud- move agor = agor- open Irregular Stems However, some VNs add and -i-, or make an internal change, e.g.: derbyn = derbyni- accept/receive dal = dali- catch dianc = dihang- escape ennill = enill- win aros = arhos- wait dweud = dwed-, or wed- or dywed- say/tell List of some common irregular stems addo = addaw- promise amgau = amgae- enclose aros = arhos- wait cau = cae- close/shut cerdded = cerdd- walk cyfnewid = cefnewidi- exchange cymryd = cymer- take cynnal = cynhali- hold (a meeting) cyrraedd = cyrhaedd- arrive, reach dadlau = dadleu- argue dal = dali- catch derbyn = derbyni- accept/receive dianc = dihang- escape dweud = dwed-, or wed-, or dywed- say/tell dychwelyd = dychwel- return ennill = enill- win gadael = gadaw- leave, let galw = galw- call gweld = gwel- see llenwi = llenw- fill (up/in) meddwl = meddyli- think, mean newid = newidi- change rhedeg = rhed- run sefyll = sef-, or saf- stand troi = tro-, or trodd- turn yfed = yf- drink ymadael = ymadaw- leave (intransitive) ymweld = ymwel- visit