How now brown cow? Learn about the vowel diphthong "ow" with a fun activity! "But 'w' isn't a vowel!" your kid might say. Well...vowel diphthongs don't always contain two vowels, something a vowel and a consonant come together to produce a complex vowel sound! Your child can find out all about these gliding vowel sounds with this colorful worksheet containing a fill-in-the-blank activity and word search.