Vowel articulation and description

This video just has a plain transcript, not time-aligned to the videoVowels are speech sounds that are produced with an open vocal tract, meaning that the articulators (that is the lips, teeth and tongue) do not obstruct airflow coming out of the mouth in any way. This video describes vowel production with a focus on the vowel qualities that are represented by symbols in the IPA chart.
While the positions of the lips and tongue have an effect on the vowels that are produced, the vowels of the IPA are also defined in part by the auditory impressions, and their qualities relative to one another.
The vowels of the IPA are therefore abstract and do not represent the vowels of any particular language. Instead, they are intended to serve as reference points that we can use to describe vowels in actual languages.
The articulatory basis of vowel sounds relates primarily to extreme tongue positions. These tongue positions were first described by Daniel Jones using x-ray and lead chains placed along the surface of his tongue – not a method that would be allowed today!
Here we can see four vowels that were documented using this method. In each of these images, the upper and lower jaw is visible, as well as the lead chain, which appears as a dotted line following the curve of the tongue.
In the upper left, we can see that the body of the tongue is raised toward the hard palate, and the highest part of the tongue is relatively far forward. This is a production of the cardinal vowel [i].
In the upper right, the tongue dorsum is raised toward the soft palate, with the highest point being relatively far back. This is a production of the cardinal vowel [u].
The lower right image shows a vowel where the dorsum of the tongue is very low and pulled back toward the throat. This is a production of the cardinal vowel [ɑ].
Finally, the lower left image shows a vowel where the tongue body is pulled down away from the palate, with the highest point of the tongue more forward than the [ɑ] vowel. This is a production of the cardinal vowel [a].
If we compare these tongue shapes to each other in a single image, the relative positions of the tongue body become more obvious. These positions represent extreme articulations, which we can therefore use to define an abstract vowel space that encompasses all possible vowel sounds.
This space is represented in the IPA as a stylized quadrilateral with the four corners defined by the vowels [i], [a], [ɑ], and [u].
The following MRI videos show an interior view of the vocal tract during the production of these four vowels.
The cardinal vowel space is then divided into four evenly spaced vowel heights by placing two vowel qualities between the corner vowels from high to low. Together, the resulting 8 vowels are known as the primary cardinal vowels.
The following clips provide a demonstration of all 8 primary cardinal vowels. Was you watch take notice of the position of the tongue during production of the vowel. Compare it to the previous production and those that come after it.
One further dimension of vowel quality remains to be described – that of lip rounding. The lips and tongue function independently of each other to affect vowel quality. The IPA vowel chart captures this by providing symbols for rounded and unrounded vowels at all combinations of height and advancement.
The set of secondary cardinal vowels differs from the primary set only in the parameter of lip rounding. For the most part this means that front vowels in the secondary set will be rounded, while back vowels will be unrounded. However, the low back vowel is an exception to this pattern where the rounded vowel occurs in the secondary set, and the unrounded vowel in the primary set.
As you listen to the following pairs of vowels, notice how the lips of the speaker protrude as she produces a rounded vowel, and remain relatively neutral when she produces and unrounded vowel. Try to see if you can make vowels that differ only in lip rounding with the same height and advancement.
Two further vowels at the top of the chart complete the cardinal vowel set. These are the high central rounded and unrounded vowels.
The remainder of the vowel chart represents vowel qualities that are more or less intermediate between the cardinal vowels that have been established. These include central vowels at the close-mid and open-mid heights, vowels at the near-close height, front and back, one at the near-open at the front, and schwa at the center. In each case the same principle of rounding and unrounding holds. Specific vowels of specific languages are often transcribed using the nearest IPA vowel symbol, though these may also be modified for more precision with diacritics