Gwenhwyseg or Y Wenhwyseg (also called "Gwentian" in English) is a Welsh dialect of South East Wales.
One of Gwenhwyseg's characteristics is the change in the long a vowel to a long e e.g. y Ted a'r Meb a'r Ysbryd Glên rather than the standard y Tad, y Mab a'r Ysbryd Glân ("the Father, the Son and the Holy Spirit").
The diphthong ae is changed in the same way: This is a diphthong which varies in pronunciation over the Gwenhwyseg territory and not realised with same phoneme; it is also found in words like pen, pren, pert, etc.
This does not occur in monosyllabic words containing a short a like mam and naw as happens in some of the dialects of Montgomeryshire.
reflects Welsh Beth sy' arni hi?.