You adjust the "Height" of a vowel by moving your tongue either up or down.. Do as the speaker in the audio below and alternate between "UUUU!" and "AAAA!" out loud to yourself. As you do this, try to develop an awareness of the direction in which your tongue is moving. When alternating between these two sounds, you should notice both your tongue and lower jaw moving UP and DOWN.
Vowel Height Awareness by You should have noticed that your tongue and lower jaw have to move all the way down to create the "AAAA!" sound. Since this movement opens up the oral cavity more, we define this vowel sound as OPEN. On the other end, the tongue has to move almost all the way UP until it almost completely blocks the oral cavity to create the "UUUU!" sound. For this reason, we define this vowel sound as CLOSE.
Vowel Backness Awareness
Here, you should have noticed that your tongue must move forward toward your teeth to make the "EEEE!" sound; we define this vowel sound as a FRONT vowel. To go back to the "UUUU!" sound, you have to retract your tongue back deeper into your mouth. As such, we define this vowel sound as a BACK vowel.
Visualizing Vowel Tuning
Once you have this connection, you should physically know what to do when I say, "Your pronunciation here is too CLOSED; this vowel should be more OPEN." As you advance through the song lessons and submit audio recordings of yourself, this is the kind of feedback I will give you. When you think you are comfortable with everything on this page, move on to the next one to start "tuning" your Portuguese vowels.
Once you have finished this page, move on to Oral Vowel Tuning.