Humanities › English Basic Grammar: What Is a Diphthong? Vowel Sounds That Morph in a Single Syllable Share Flipboard Email Print In most dialects of English, the vowel sounds in these words are diphthongs. Illustration by Claire Cohen. 2018 ThoughtCo. English English Grammar An Introduction to Punctuation Writing By Richard Nordquist Richard Nordquist English and Rhetoric Professor Ph.D., Rhetoric and English, University of Georgia M.A., Modern English and American Literature, University of Leicester B.A., English, State University of New York Dr. Richard Nordquist is professor emeritus of rhetoric and English at Georgia Southern University and the author of several university-level grammar and composition textbooks. Learn about our Editorial Process Updated on November 04, 2019 The word "diphthong" comes from the Greek and means "two voices" or "two sounds." In phonetics, a diphthong is a vowel in which there is a noticeable sound change within the same syllable. (A single or simple vowel is known as a monophthong.) The process of moving from one vowel sound to another is called gliding, which is why another name for a diphthong is a gliding vowel but they are also known as compound vowels, complex vowels, or moving vowels. The sound change that turns a single vowel into a diphthong is called diphthongization. Diphthongs are sometimes referred to as "long vowels" but this is misleading. While vowel sounds do change in a diphthong, they do not necessarily take more time to say than a monophthong. Diphthongs in American English How many diphthongs are there in the English language? It depends on which expert you ask. Some sources cite eight, others as many as 10. Even syllables containing a single vowel can contain a diphthong. The rule of thumb is: If the sound moves, it’s a diphthong; if it's static, it’s a monophthong. Each of the following diphthongs is represented by its phonetic symbol. /aɪ/ This diphthong creates sounds similar to "eye" and most often occurs with letter combinations that include /i/, /igh/, and /y. Examples: crime, like, lime /eɪ/ This diphthong creates sounds similar to “great” and is most often used with letter combinations that include /ey/, /ay/, /ai/ and /a/. Examples: break, rain, weight /əʊ/ This diphthong creates sounds similar to “boat” and most often occurs with letter combinations that include /ow/, /oa/ and /o/. Examples: slow, moan, though /aʊ/ This diphthong creates sounds similar to “ow!” and most often occurs with letter combinations that include /ou/ and /ow/. Examples: brown, hound, now /eə/ This diphthong creates sounds similar to “air” and most often occurs with letter combinations that include /ai/, /a/, and /ea/. Examples: lair, stair, bear /ɪə/ This diphthong creates sounds similar to “ear” and most often occurs with letter combinations that include /ee/, /ie/ and /ea/. Examples: beer, near, pier /ɔɪ/ This creates sounds similar to “boy” and most often occurs with letter combinations that include /oy/ and /oi/. Examples: oil, toy, coil /ʊə/This diphthong creates sounds similar to “sure” and most occurs with letter combinations that include /oo/, /ou/, /u/, and /ue/. Examples: lure, pure, fur Diphthongs in Dialects One of the most interesting ways in which diphthongs relate to spoken language is in how they’ve evolved into regional accents and dialects from their languages of origin. In the borough Brooklyn, for example, when someone says, “Let the dog out,” the word dog contains a distinctive “aw” sound so that “the dog” becomes a “dawg.” Cite this Article Format mla apa chicago Your Citation Nordquist, Richard. "Basic Grammar: What Is a Diphthong?" ThoughtCo, Aug. 27, 2020, thoughtco.com/diphthong-phonetics-term-1690456. Nordquist, Richard. (2020, August 27). Basic Grammar: What Is a Diphthong? Retrieved from https://www.thoughtco.com/diphthong-phonetics-term-1690456 Nordquist, Richard. "Basic Grammar: What Is a Diphthong?" ThoughtCo. https://www.thoughtco.com/diphthong-phonetics-term-1690456 (accessed January 21, 2022). copy citation Watch Now: Should You Use A, An or And?