Look in a mirror and say the sounds in these words: ” ea”(scream), “i” (flip), “e” (jet), “a” (tan). What do you notice about the jaw? It gets wider and wider for every word.
Look closely at your tongue and you can see for each word the tongue gets more deflated with every word (from scream to tan). The midline of the tongue actually deflates like a beachball on steroids when you transition from an “e” to an “a” sound.
Sometimes my students don’t pronounce words like apple properly. Instead of /ˈæp.əl/ they say, / ˈep.əl/. In such scenarios, you can get them to place their finger between their teeth and say / ˈep.əl/. If they can feel a gentle bite then you need to open up and say /ˈæp.əl/. You need to strain the cheek muscles to see you are doing it right. If you can fit in two index fingers between teeth, you are probably generating this æ sound correctly.
Here’s a colorful phrase you can memorise for all the front vowel sounds in order of increasing jaw height:
SCREAM, FLIP the JET and get a TAN!