This chapter has defined the English vowel system, first by enumerating the lexical sets which are useful in comparing the sound classes of English dialects, and then by structural characterization of the temporal and static aspects of vowel phonology in a useful, hypothetical dialect, Reference American. The result is an extremely simple, underspecified, phonological structure making use of privative features:
Vowel Nucleus (Glide)
Vowel licenses Height ({[high], [low]}), ([front]).
Thus, English vowels consist sequentially of a nucleus, followed
sometimes by a glide. [front] and the height features [high] and
[low] are licensed within vowels. Redundant features [rhotic] and
[round] are filled in, it was argued, by language-specific phonological
rules. Finally a set of universal phonetic implementation rules was
proposed which relates the minimally specified phonological categories
to actual phonetic forms. The phonetic and phonological patterns of
Reference American will be used as a basis for comparison for the
English dialects studied in the remainder of the thesis.