Explore one of the trickier vowel teams as you practice reading vowel diphthongs: ou. A diphthong, or special vowel sound, is a powerful two-letter combination. It completely changes how a word sounds! In this spelling worksheet, kids practice decoding and understanding words with the diphthong ou, such as “blouse,” “sound,” or “ounce.” This worksheet pairs well with the first and second-grade curriculum and builds letter-sound relationships.