We can ‘hear’ the differences among ‘night rate’, ‘nitrate’, and ‘Nye trait’. That is, these three are kept apart by difference of sound. Any difference of sound which functions to keep utterances apart is by definition part of the phonological system of the language—and every such difference must be provided for by our analysis and our notation. What has been overlooked is a contrast between two different ways in which a speaker of English can get from one vowel or consonant to the next—two different kinds of ‘transition’ between successive vowel and consonant phonemes.
- Hockett (1958), Pag. 54