How to Pronounce American English Diphthongs

American English diphthongs are “moving vowels” that start in one position and glide to another within a single syllable. Mastering these sounds helps your English sound more natural in meetings and on calls with your colleagues and clients.

What is a diphthong?

A diphthong is one vowel sound that contains a glide between two tongue positions. In American English, this glide is very important for sounding confident and professional because it affects key words such as “data,” “client,” and “deploy.”

When non-native English speakers skip or reduce this glide, diphthongs can sound like a simple vowel and may cause misunderstandings, especially on calls or in fast technical conversations. On this page, you will learn the five main American English diphthongs and practice them with work-related vocabulary.

The five American English Diphthongs

These are the diphthongs you will practice in your US Pronunciation lessons:

• /eɪ/ as in “update,” “database,” “stakeholder”​
• /aɪ/ as in “time,” “client,” “my”​
• /ɔɪ/ as in “deploy,” “voice,” “invoice”​
• /aʊ/ as in “outage,” “downtime,” “cloud”​
• /oʊ/ as in “scope,” “workflow,” “remote”

Each lesson focuses on one diphthong and uses examples from IT, engineering, and project work so you can use the sound immediately in your job.

How to use these lessons

• Click the diphthong images or the links below to open the free lesson page for that sound, where you will find targeted practice with work vocabulary and model sentences.
• Use the IPA Chart page as your “map”: when you are unsure about a sound during a meeting or when preparing a presentation, come back here and jump directly to the diphthong you need.

Next steps

• Choose one diphthong that gives you the most trouble in your work communication and complete its lesson first.​
• After each lesson, record yourself saying key sentences from your real job tasks—status updates, stand‑up reports, or client emails—and compare your glide to the model.