<P> Dionysius Thrax calls consonants sýmphōna "pronounced with" because they can only be pronounced with a vowel . He divides them into two subcategories: hēmíphōna, semivowels ("half - pronounced"), which correspond to continuants, not semivowels, and áphōna, mute or silent consonants ("unvoiced"), which correspond to stops, not voiceless consonants . </P> <P> This description does not apply to some human languages, such as the Salishan languages, in which stops sometimes occur without vowels (see Nuxálk), and the modern conception of consonant does not require co-occurrence with vowels . </P> <P> The word consonant is also used to refer to a letter of an alphabet that denotes a consonant sound . The 21 consonant letters in the English alphabet are B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, X, Z, and usually W and Y . The letter Y stands for the consonant / j / in yoke, the vowel / ɪ / in myth, the vowel / i / in funny, and the diphthong / aɪ / in my . W always represents a consonant except in combination with a vowel letter, as in growth, raw, and how, and in a few loanwords from Welsh, like crwth or cwm . </P> <P> In some other languages, such as Finnish, y only represents a vowel sound . </P>

When does the letter w have the characteristics of a consonant