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ENGLISH·COURSE
Course outline

Diphthong Sound /ɔɪ/

Video lesson. The full description lives in the linked notes (Resource below).

The /ɔɪ/ diphthong: from a rounded /ɔ/ into /ɪ/

The /ɔɪ/ starts on a mid-back vowel with rounded lips and glides toward a high front vowel. Your lips travel from rounded to spread over the course of the sound, and that journey is what you practice here.

How it's made

  • 👄 Mouth: lips rounded at the start, spread by the end.
  • 👅 Tongue: back and mid at the start, forward and high at the end.
  • 🔊 Voice: voiced and long, with the weight on the first part.

You hear it in: boy · noise · toy · voice · coin

⚠️ The typical Spanish-speaker mistake: starting on the closed Spanish o. The English first element is far more open: boy doesn't begin at bo, it begins closer to baw.

By the end you'll be able to: open that first element and carry your lips from rounded to spread without breaking the sound.