The letter W can sometimes be the second part of a vowel sound as in words like such as "cow", "bow", or "how". In these words the vowel has the sound of /aʊ/. The letter W can be used as a consonant sound at the beginning of in the words "when", "where", "wet". In some languages, like Welsh, the letter W represents the vowel sound /ʊ/, like "cwm" (a kind of valley).