The 'oh' as in 'no' diphthong. The first sound of this diphthong does not occur on its own as a vowel in American English, o, o, oh. You can see the lips have a rounded position, o, oh. The tongue raises up a bit in the back towards the soft palate. In general, the tongue raises some and shifts back a bit, o, o. This means the tip of the tongue, pulled slightly back, is not touching anything. The second sound is the 'uh' as in 'pull' vowel sound, though, in this diphthong, the lips will round more for the second sound than when the 'uh' as in 'pull' occurs on its own as a vowel. Oh, you can see that tighter circle. The back part of the tongue will stretch even further towards the soft palate in the second half of this diphthong. The tip of the tongue, usually touching behind the bottom front teeth for the 'uh' as in 'pull' vowel, may be slightly further back because it was further back in the first half of the diphthong. Oh, no.
Here we see both sounds of the diphthong. In the first sound, you can see the jaw is dropped more. In both sounds the lips are rounded, but they are more rounded in the second sound. Here are the two sounds in profile. Again, note that the jaw has dropped more for the first sound. Here, parts of the mouth are drawn in. In the first sound, the tongue is pulled slightly back and up. In the second sound, it stretches up even more towards the soft palate. In both sounds, the tongue tip is not quite touching the bottom front teeth. Sample words: lonely, owner, telephone. Sample sentence: The window of the hotel was blown out and broken. Now you will see this sentence up close and in slow motion, both straight on and from an angle, so you can really study how the mouth moves when making this sound.
The. Tongue through the teeth for the TH sound. Window, lips make the W shape, tongue up for the N. Teeth together for the D. And here a quick 'oh' as in 'no' diphthong. Of, bottom lip up for the V, the hotel, again, 'oh' as in 'no', 'eh' as in 'bed', and the tongue up for the L. Was blown, the 'oh' as in 'no', you can see the lips rounding more at the end. Out, with the 'ow' as in 'now' diphthong. And broken. Lips together for the B, R, and here is the 'oh' as in 'no' diphthong. Broken.
And from an angle. Tongue through the teeth for the TH. The window, lips make the W. Tongue up for the N and D. And here is an 'oh' as in 'no'. You see the lips round more at the end. Of the ho-, again 'oh' as in 'no', you see the tongue move back, hotel. Lips together for the T. 'Eh' as in 'bed' and the tongue comes forward for the L. Was blown, lips together for the B. Tongue up for the L and down, 'oh' as in 'no', again you see the tongue moving back. Tongue up for the N. Out. Teeth together for the T. And broken, lips together for the B, again an 'oh' as in 'no' diphthong, forming a tight circle at the end. Broken. Tongue tip up to make the N. That's it, and thanks so much for using Rachel's English.