/aʊ/

The /aʊ/ sound in English is a diphthong, which means it’s a complex vowel sound that starts with one vowel (/a:/ as in ‘car’) and transitions to another (/ʊ/ as in ‘book’) within the same syllable. Here’s how you pronounce it:

• Position your mouth and tongue: For the /aʊ/ sound, your mouth should initially be wide open (for the /a:/ part), with your tongue low in your mouth. As the sound transitions to /ʊ/, your mouth closes a bit and your tongue moves up and back. Your lips are unrounded at the start and become more rounded as you transition to the /ʊ/ sound.
• Voicing: The /aʊ/ sound is a voiced vowel, meaning your vocal cords vibrate when you produce this sound. You should feel a vibration if you lightly touch the front of your throat while saying the sound.
• Release the sound: With your mouth and tongue in the correct positions, let your breath flow out over your tongue and through your mouth. As you make the sound, smoothly transition from the /a:/ position to the /ʊ/ position. The vocal cords vibrate to produce the /aʊ/ sound.