Translation:Tri deg chwech ceiniog
"Chwech" causes an aspirate mutation. So it's "Chwe cheiniog". Due to the fact that the aspirate mutation is diminishing in usage "Chwe ceiniog" could also be considered correct.
Thank you. Same as "punt" goes to "phunt". I need to revise aspirate mutations.
p t c go to ph th ch - very regular in spelling.
From what I have heard, c to ch is most alive in the daily speech of fluent speakers while the others are becoming less common and to insist on them may make you sound slightly odd in some contexts (such as after a "and"), though they're still required in formal writing I believe.