What is a Vowel?

Though most English speakers have learned that the vowels are A, E, I, O, U, and sometimes Y, this is an oversimplification. And many of us who can rattle off this memorized list and say that these letters are vowels have absolutely no idea why.

There are actually 15 vowel sounds and 28 written vowels in English. Rather than memorizing information that is inaccurate, it is much more helpful to learn the actual definition of what a vowel is.

A vowel is a sound that is unblocked by the tongue, teeth, or lips. The mouth is open. Vowel sounds can be sustained or sung and can be made louder and softer.

To experience this for yourself, say the word “Help.” Now drop the vowel: “Hlp.” Then try to call loudly for help without saying the vowel. . . “HLP! HLP!” It doesn’t work very well.

Knowing the definition of a vowel sound also explains the “and sometimes Y” that many of us memorized as part of the list. Y says a vowel sound in fly, memory, and cyclical. It is not a vowel in yellow, yield, or young. Determining whether it is a consonant or vowel depends on the sound it is making in a particular word, not on the written letter.

English has 15 discrete vowel sounds. They are written 28 different ways in common English words:

Sound English spellings
/ă/ a
/ā/ a, ai, ay, ea, ei, ey, eigh
/ä/ a, au, aw, augh
/ĕ/ e, ea
/ē/ e, ea, ee, ei, ey, i, ie, y
/ĭ/ i, y
/ī/ i, y, igh, ei, eigh
/ŏ/ o, ough
/ō/ o, oa, ou, ow, oe, ough, oo
/ö/ o, oo, ew, ou, u, ui, oe, ough
/ŭ/ u, ou
/ū/ u, ew
/ü/ u, oo
/oi/ oi, oy
/ow/ ou, ow, ough

The R-controlled phonograms also act as vowels within words. This is because the sound /r/ has some properties of a vowel and some properties of a consonant. /R/ can be sustained. It can be controlled for volume. However, it is blocked by the tongue; therefore, on its own it is a consonant. When the sound /r/ follows a vowel, though, the /r/ sound often dominates the vowel sound. This creates the phonograms ER, IR, UR, EAR, AR, and OR.

If you were to try to memorize each of the vowels by rote, it would be overwhelming! However, when students understand the definition of a vowel and how to test it for themselves, it is easy. We teach students how to test whether a sound is a vowel or a consonant starting in Lesson 13 of Foundations and Lesson 1 of Essentials, and we’ve found that even young children grasp the concept quickly and are able to apply it to new sounds that they learn. For example, they will recognize that the word dough comprises one consonant sound, /d/, and one vowel sound, /ō/, here spelled with the four-letter phonogram -OUGH. It is not three consonants and two vowels! They will understand that in onion the I is saying the consonant sound /y/ and is not functioning as a vowel.

Having an accurate understanding of vowels in turn also strengthens students’ ability to identify syllables and gives them an important tool for success in spelling.

This post is the first in a six-part series on the Logic of English Blog! Check out the others:

UP NEXT:What is a Consonant?
Understanding and Counting Syllables
Introducing Spelling Rule 31!
What is a Schwa? Helping Students Read and Spell the Schwa Sound
The Clever Monks and the Lazy O: Why O sometimes says /ŭ/

A full Sound to Spelling reference with all of the English sounds, each of their spellings, and sample words is available in the Logic of English Spelling Journal.