tourWe have mentioned the vowel quadrilateral before, in our post about learning new vowel sounds. The vowel quadrilateral is a four-sided shape marked with symbols representing different vowel sounds. It serves as a useful visual tool for describing what you need to do with your mouth to produce a target vowel sound.

The challenge of learning new vowels is describing them. How do you describe the sound in the middle of the word cat? If you’re well-versed in the International Phonetic Alphabet, or IPA, you can just write the sound as ӕ. However, how do you describe the sound of that vowel? Using the vowel quadrilateral, this is possible.

One Version of the Vowel Quadrilateral

One Version of the Vowel Quadrilateral

The vowel quadrilateral describes sounds by placing them on a point somewhere between two opposites. The two main oppositions are high-low and front-back. On the vowel quadrilateral, high is at the top and low is at the bottom. (What a surprise.) Front is toward the left, and back is toward the right.

The high-low opposition describes the height of the tongue during production of the vowel, and the front-back opposition describes the degree to which the tongue is at the front of the mouth or at the back of the mouth. As you might imagine, these oppositions are not binary. In other words, there are many positions between the highest and lowest and most front and most back positions.

Since there are many positions between high and low and front and back, people use other descriptors to describe vowels. Mid is used along the high-low axis and central is used on the front-back axis. The very middle of the vowel quadrilateral – in mid-central position – is where you can find schwa, written ә in IPA, the most neutral of the vowels. A schwa is what you get when you open your mouth a bit and let your voice out. (Like in unstressed the.)


By protruding the tongue and blowing forcefully, the result is called a ‘raspberry’. It is not a speech sound, but boy, is it fun to do!

Another descriptor used when talking about vowels is roundedness, which is typically all or nothing. Roundedness refers to whether or not the speaker is rounding his lips. So a vowel sound like the one in the middle of the word booth is rounded, but the vowel sound in the middle of ball is not. Any spot on the vowel quadrilateral can have two vowels that correspond with that spot: one is rounded, one is not rounded. (In a French course I took many years ago, to learn some of the trickier vowels in the Language of Love, I was instructed to produce a rounded vowel I could already produce, but without rounding my lips. It worked!)

Arguably, when speaking English as a second language, the vowels are the most critical sounds of speech for the listener to understand the speaker. The difficult part about mastering the vowels of any language is figuring out what your mouth needs to do to come up with a perfect production. Luckily, we have the vowel quadrilateral and professionals specializing in accent modification to help you learn.

Contact us to improve your vowels today! After all, people should hear your ideas, not your accent.