This document provides information about diphthongs and examples of common diphthongs. It defines diphthongs as sounds formed by combining two vowel sounds within a single syllable, with the sound beginning as one vowel and moving to another. It lists the most common diphthongs as oy, oi, ou, and ow, and provides words as examples for each diphthong sound. The document goes on to provide questions and activities for students to complete related to identifying words with vowel diphthongs.