Some components which are commonly extracted by linguists merely because they consist of pitch or stress features have no basis for being thus extracted except the phonetic considerations of this section. Such, for example, are the tones in languages where each vowel in a morpheme has an arbitrary phonemic pitch. As far as distributional simplicity goes we could just as well state that a language has not, say, 5 vowels and 3 tones, but 15 vowel phonemes (high /ì/, mid /i/, low /ì/—all of which might differ in quality as well as pitch; high /é/, etc.). If these vowels have not already been completely broken down into components on distributional grounds, we may now extract the tones as components on grounds of phonetic simplicity.
- Harris (1944), a pag.200