[Dr Q] Whilst Rosie is correct, there is a consonant which substitues for 'x' but which is reserved for the Elders (and is oft referred to as a 'gift from the faeries'); they clack their false teeth! .... Sorry, just feeling frivolous.
Also no "J", "K", "Q", "V" or "Z". BUT - "CH", "DD", "FF", "LL", "NG", "RH", "TH" and one other digraph (can't remember which) all count, so Welsh has a 28-letter alphabet.
(Herr Bratsche) It's "PH" you're after. It only occurs as a mutation, i.e. a changed beginning to a word, which would otherwise start with "P". In my last post I left out an "h" in Nghymraeg, another mutation, as you can see. Many North Walians cannot pronounce the "zh" sound in words like "decision". It comes out as "sh".
Had our dress rehearsal last night (hence absence from epilg). We're hoping that the age-old adage of "Crap dress rehearsal, good first night" holds true. For some reason, the only bit that got practiced twice was the bows. Something which I find to even practice once a little offensive... *grumble - bloody thesps - mutter*