Master vowel words with simple lists, tips, and examples. Boost your spelling and exam skills-start learning now! What Is a Vowel ? The term ‘ vowel ’ is used to refer to letters used to represent vowel sounds. In the English language, five letters among the twenty-six letters of the English alphabet are called vowels . They are a, e, i, o, and u. The Oxford Learner’s Dictionary defines a vowel as “a letter that represents a vowel sound”. Now, let us find out what a vowel sound is. Learn how to pronounce the 20 vowel sounds in English with the International Phonetic Alphabet (IPA) symbols and examples. Find out the categories, spelling patterns, and exceptions of vowel sounds in English. Learn how to identify and use vowel sounds in words , sentences and poetry. Find out the difference between short and long vowels, diphthongs and examples of each vowel sound.