The 'ai' as in 'buy' diphthong. The first
sound of this diphthong does not occur on its own as a vowel in American English. A,
a, ai. It's similar to the 'aa' as in 'bat' in that the back of the tongue raises towards
the soft palate, but it doesn't raise as high as it does in the 'aa' as in 'bat' vowel,
a, a, ai. Also, you may find that the corners of the lips pull out a little bit, and the
top lip raises a bit, exposing some of those front teeth, a, a. The tip of the tongue remains
forward in this sound, lightly touching behind the bottom front teeth. The second sound of
the diphthong is the 'ih' as in 'sit'. In this sound, the tip of the tongue is also
forward, touching just behind the bottom front teeth. So that does not move in this diphthong.
However, the front/mid part of the tongue does raise towards the roof of the mouth,
ai, ai. So as it reaches up towards the roof of the mouth, the jaw will close somewhat,
ai, ai, buy. Here we see the two sounds of this diphthong. You can see in the first sound,
aa, that the jaw is more dropped. On the second sound, 'ih', the tongue is more forward. Here
are the two sounds in profile. Again, note that in the first sound, the jaw is dropped
more. Here, parts of the mouth are drawn in. you can see that the tongue position in the
first sound is drawn slightly back, which makes it flatter. In the second sound, the
tongue is much more raised in the front. In both sounds, the tip of the tongue does lightly
touch behind the bottom front teeth. The 'ai' as in 'buy' diphthong. Sample words: shy,
write, good-bye. Sample sentence: My sister is bright with a nice sense of style. 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. My, lips press together
for the M, jaw drops, here's the 'ai' as in 'buy' diphthong, you could see the tongue
come up towards the end. Sister is bright, lips come together for the B. And here it
is again, the 'ai' as in 'buy' diphthong. Tongue down and then pushes up towards the
front. The tip goes up to make the T. Lips come together for the W. With a nice - tongue
up for the N and drops for the 'ai' as in 'buy' diphthong. Sense of, lip comes up to
make the V sound, style. Another 'ai' as in 'buy' diphthong. Jaw drops for the first part,
tongue moves up for the second part, and the dark L. Now from the angle. My, 'ai' as in
'buy' diphthong. Jaw drops for the first part and then the middle-front part of the tongue
moves up for the second part. Sister is bright, another 'ai' as in 'buy'. Jaw drops, forward
part of the tongue moves up, and now here the tip goes up to make the T. With a, tongue
tip up to make N and drops, ai, nice, sense of, lip up to make the V sound. Style, another
'ai' as in 'buy' diphthong. Jaw drops, tongue is down, and then the mid-front part of the
tongue raises to make the second part of the diphthong. That's it, and thanks so much for
using Rachel's English.