What Is a Diphthong?

 A Diphthong is when two vowel sounds become one.

A diphthong is a single syllable that begins with one vowel sound and glides into another. Unlike a pure vowel (called a monophthong), which has a steady, unchanging sound (like /iː/ in seat), a diphthong shifts from one position in the mouth to another during articulation.

Examples of Diphthongs in English

Picture 1.
The diagram for the four diphthong sounds.

Note. Taked from Martinez M (2025) | Diphthong Sounds. https://www.canva.com/design/DAGlGLng22A/po9d6NuRVdgYu8DXtRoswQ/edit

I'm leaving you a super useful video to practice the pronunciation of diphthongs!