Words beginning with p, t, c, b, d, g, m, ll and rh take a soft mutation after the pronoun ei (his), e.g.

ei gymhwyster, ei fwriad, ei lwybr, ei broblem, ei dasg.

Rwy’n ‘nabod Rhys a chredaf ei fod yn dweud y gwir.

Words beginning with p, t and c take an aspirate mutation after the pronoun ei (her), e.g.

ei chymhwyster, ei phroblem, ei thasg.

When ei (her) precedes a noun which begins with a vowel, h is added to the noun, e.g.

ei hamser, ei hysgol, ei harian.

The table of mutations can be found by clicking here.