Other vowel parameters

The differences between vowels that we've seen so far all involve the position of the tongue body. There are other articulators that function independently of the tongue body which can also change the vowel sound. Some quick examples:

As with consonants, the vocal cords may or may not be vibrating regardless of what the rest of the vocal tract is doing. Vowels are almost always voiced. But a few languages have contrastive voiceless vowels (that is, the word can mean something different if your vocal cords aren't vibrating during the vowel). English has a few environments where vowels may be (non-contrastively) voiceless.
As with consonants, air may or may not be flowing through the nose, regardless of what the tongue or lips may be doing. Vowels tend to be oral, but many languages also have a set of nasal vowels (e.g., French). English has a few environments where vowels may be (non-contrastively) nasalized.
The tongue tip may be curled back to perform a retroflex approximant, whatever the tongue body is doing. The "R-colouring" that this adds to the vowel is often called rhoticization.
And the most common second constriction gesture of all:

Rounding

The lips may either be in their normal position or they may be rounded. The English vowels [u], [

], [o], and [

] are rounded. The rest are unrounded. (In Canadian English, the sound we have been writing as [

] is also often somewhat rounded.)

	front	central	back
high	unrounded	unrounded	rounded
mid	unrounded	unrounded	rounded
low	unrounded	unrounded	unrounded

This pattern of rounding and unrounding is especially common across languages. But it is logically possible for any tongue body position to cooccur with either rounding or unroundedness. For example, the vowel transcribed as [y] -- the u of French lune [lyn] 'moon' or the ü of German grün [gryn] 'green' -- is nothing more than an [i] pronounced with the lips rounded instead of unrounded.

Tense and lax

We aren't finished yet. We still have no way to tell the difference between the pairs of sounds which occur in some squares of the tic-tac-toe chart:

[i] and []
[e] and []
[u] and []

In pairs like this, the sound given higher in the chart is called tense and the one given lower is called lax. In general, tense vowels are more "extreme" than lax vowels, both vertically and horizontally:

Tense vowels tend to have the position of the tongue body slightly higher than the corresponding lax vowels.
Lax vowels tend to be more centralized than the corresponding tense vowels (i.e., closer to schwa in the front/back dimension).

We will discuss the physical differences between tense and lax vowels more fully later in the course.

The tense vowel [o] also has a lax counterpart, the "open o" which we have so far seen only in the diphthong [oj]. In many dialects of English, the historical distinction between [] and [] has been preserved:

cot [kt]
caught [kt]

In most dialects of Canadian English, all former [

] words are now pronounced with [

], creating many new homonyms. [

] is used only in the diphthong [

j] and by many speakers before [

] (the vowel in or is in fact between [o] and [

] -- speakers vary as to which of the two it's closer to).

Hint: The IPA symbols make it easier to remember which vowels are tense and which are lax. The tense vowels all have normal English letters: [i], [e], [u], [o]. The lax vowels all have something weird: [], [], [], [ open-o ].

Next: Glides
Previous: Vowel charts (1)
Up: table of contents