To speak Welsh, you need to know that it has a different alphabet than used in English and has a phonetical (say what you see) approach; it has 28 letters, 7 vowels. 21 consonants and 13 dipthongs. Here are the 28 letters:
a, b, c, ch, d, dd, e, f, ff, g, ng, h, i, l, ll, m, n, o, p, ph, r, rh, s, t, th, u, w, y
The dipthongs are: Ae Ai Au Aw Ei Eu Ew I’w Y’w Oe Ow Wy Ywy.
The letter “j” is now often included in the alphabet, between “i” and “l”, due to its use in several loanwords from English (especially the common surname Jones). The letters “k”, “v”, “x” and “z” are used in some technical terms, like kilogram, volt and zero. http://www.wales.com/welsh-alphabet.
The use of the inflection or ‘tô bach’ over some letters change the sound of the letter to a long a, e, o. or y. (e.g. cân, pêl, Tŷ)