The high–low dimension

High vowels have the tongue raised most towards the roof of the mouth; if the raising was significantly greater, then friction would be produced, making a fricative consonant, not a vowel. The high vowels from the last section are in (4).

Low vowels are those where the tongue is not raised at all, but rather lowered from its resting position: when you produce a low vowel, you will be able to feel your mouth opening and your jaw dropping, even if it is not very easy to figure out quite what your tongue is doing. Low vowels are given in (5).

Again, there is a further class intermediate between high and low, namely the mid vowels, shown in (6). These can if necessary be further subclassified as high mid (like the face and goat vowels) or low mid (like the dress, thought, strut vowels) depending on whether they are nearer the high end of the scale, or nearer the low end.