The Shape of Vowel Space

The first and second formant frequencies are measured at the phonetic nucleus of the acoustic vowel corresponding to 1890 vowel tokens taken from a conversation between Vince and Santa Ana.^9.18 Figure  shows the general shape of LACE F1-F2 space.

Figure: 1890 raw measurements of F1, F2.

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Only a few general facts can be learned from a chart like this. First, the overall distribution is roughly triangular, though it has a more vertical back edge than, for example, the Jamaican Creole (JC) vowel space, suggesting a phonetic fronting of the higher back vowels in LACE. This confirms the impressionistic finding above that the phoneme /u:/ is realized well to the front of [u].

It is interesting to make a slightly more detailed comparison with one of the corresponding charts, made for Jamaican Creole vowels (cf. page ). There, Juba's vowel space has a mode in the [] region, and the distribution fans up in two directions, front-and-up and back-and-up, leaving a sparsely populated area in the high-central region. In contrast, the LACE vowel space has two modes, high-front and high-back, with a lesser density of tokens occurring in the low-central area. One might summarize this difference by saying that LACE vowel space is more top-heavy than JCE vowel space. Also, LACE has less of a trough in the density of tokens in the high-central region than JC has.