Fore, blaen, blaenaf

Fork, fforch; pigfforch

Form, ffurf, dull: ffurfio

Fort, caer, castell

Foul, aflan, budr; brwnt

Four, pedwar, pedair

Fowl, aderyn

Free, rhydd: rhyddhau

Fret, anfoddloni, sori

Frog, llyffant