ii) In making the two vowels described above, it is the front part of the tongue that
is raised. We could therefore describe iand as comparatively frontvowels. By
changing the shape of the tongue we can produce vowels in which a different part
of the tongue is the highest point. A vowel in which the back of the tongue is the
highest point is called a backvowel. If you make the vowel in the word ‘calm’,
which we write phonetically as ɑ, you can see that the back of the tongue is raised.
Compare this with in front of a mirror; is a front vowel and ɑis a back
vowel. The vowel in ‘too’ (u) is also a comparatively back vowel, but compared
with ɑit is close.
So now we have seen how four vowels differ from each other; we can show this in a simple
diagram.
However, this diagram is rather inaccurate. Phoneticians need a very accurate way of
classifying vowels, and have developed a set of vowels which are arranged in a close–open,
front–back diagram similar to the one above but which are not the vowels of any particular
language. These cardinal vowelsare a standard reference system, and people being trained
in phonetics at an advanced level have to learn to make them accurately and recognise them
correctly. If you learn the cardinal vowels, you are not learning to make English sounds, but
you are learning about the range of vowels that the human vocal apparatus can make, and
also learning a useful way of describing, classifying and comparing vowels. They are recorded
on Track 21 of CD 2.
It has become traditional to locate cardinal vowels on a four-sided figure (a quadrilateral of the shape seen in Fig. 4 – the design used here is the one recommended by the
International Phonetic Association). The exact shape is not really important – a square
would do quite well – but we will use the traditional shape. The vowels in Fig. 4 are the socalled primarycardinal vowels; these are the vowels that are most familiar to the speakers
of most European languages, and there are other cardinal vowels (secondarycardinal
vowels) that sound less familiar. In this course cardinal vowels are printed within square
brackets [ ] to distinguish them clearly from English vowel sounds