It's pronounced for me as it should be. And no we have no silent letters in Welsh.
In my (limited) experience, in everyday spoken language, not everything is pronounced the way it's written -- e.g. beth might be pronounced be', gwybod as gwbod, fy mod as bo' fi and cyntaf as cynta.
Whether that's a case of "silent letters" or simply diglossia (the spoken language is not identical to the written language) might be a matter of definition.
The reason I view them as non-silent letters is because there's nothing wrong with pronouncing the "th" in "Beth" or the "f" at the end of "Cyntaf". Of course colloquially we often don't pronounce them but in formal situations we do pronounce them.