The Welsh language (called Cymraeg in Welsh) has 28 letters. The Latin alphabet is used (i.e. as in English, French, Polish, etc.), but letters sometimes represent different sounds in Welsh, which can be confusing to English speakers.
There are no silent letters. Every letter has a sound, and the sound is vocalized in spoken Welsh. The letters K, Q, V, X and Z are not included in the Welsh alphabet, but are sometimes found in borrowed words. When present, these letters have their English sounds, except for Z, which tends to be /s/ in North Wales.
There are regional differences in Welsh pronunciation, but standard Welsh is understood by Welsh speakers everywhere. The pronunciation guide below approximates the Welsh letter sounds by using standard English examples.
The vowels are A, E, I, O, U, W, and Y. All the vowels can be lengthened by the addition of a circumflex, properly called acen grom ('convex accent', or 'crooked accent') in Welsh, but often known by the familiar/juvenile name to bach (lit. 'little roof').
a is always as in can, ham, or man, never long as in may. The Welsh words am and ac are pronounced as they would be in English.
e by itself is always as in get, pet, and let. However, the letter E has a different sound in the three diphthongs.
i has the I sound as in bin or pin, or a long E sound as in seen or queen.
o has the O sound as in hot or the long sound as in toe.
u has the sound of long EE, as in see.
w has the sound of OO as in boot and shoot, or of U as in pull. Note, however, that W can also be used as a consonant with the English W sound.
y has two different sounds. In one-syllable words (llyn), and in the last syllable of polysyllabic words (estyn), it is a shortened EE sound as at the end of happy. (Note the different sound in ywy, however). In other contexts (in non-final syllables of polysyllabic words) it is pronounced as the obscure vowel schwa, as in the first syllable of the English word about (e.g. ystyr, pronounced uh s t ii r, where uh represents schwa).
The preceding rules for y apply to South Welsh accents. In areas of North Wales, the non-schwa pronunciation of y is less like English EE and more of a guttural sound, formed further back in the mouth.
Ll is a sound with no English equivalent. It is a voiceless alveolar lateral fricative formed by pronouncing L while allowing air to escape around the tongue; the English thl of athlete (or slat pronounced with a lisp) is vaguely similar.
M is the same as English M as in many.
N is the same as English N as in no or never.
P is the same as English P as in poor or party.
Ph is the same as ff
R is the same as English R as in right, but rolled.
Rh is pronounced as HR; that is, a slight H sound comes before the R sound.
S is the same as English S as in say.
Si is the same as English Sh as in show.
T is the same as English T as in turn.
Th is English voiceless TH, as in think or three. Note difference from the voiced Dd.
W, when used as a consonant, has the English W sound as in work.