This chapter has approached the Jamaican Creole vowel system from a number of directions. An analysis of the phonological structure of the JC vowel system was proposed. The overall shape of vowel formant space was compared with that of other dialects. Impressionistic transcriptions of stressed tokens of each of the vowels were listed and briefly discussed. The phonetic effects of phonological vowel length were explored: long vowels have twice the duration of short vowels, and long vowel nuclei are peripheral and shifted into the corners of the acoustic space, relative to their short counterparts. Bootstrap resampling was used to show how precise were the estimates of the mean locations for each vowel. These formant-frequency means were then characterized by an acoustic-phonetic grammar for vowel nuclei that was considerably simpler than the alternative list of mean formant frequencies. This grammar is similar to the phonetic implementation grammar given for Reference American in Section , except that it includes a number of dialect-specific phonetic implementation rules. The effects of stress on vowel quality was explored: Centralization due to phrasal stress reduction applies to the short vowels only. The differences between the effects of following /l/ in Jamaican Creole as opposed to other dialects is discussed in Chapter 10.
In Appendix 2, sound-shifts and mergers in Jamaican Creole are discussed. Evidence from other English-based Caribbean creoles is adduced to suggest a particular chain of historical sound-shifts resulting in some of the current phonetic characteristics of Jamaican Creole. Finally, because of the irreversibility of merger, it is argued that one can infer that if a basilectal variety has a merger that an acrolectal variety does not, then the acrolectal variety has existed as long as the basilectal variety.