It can occur in the height of the vowel space
(optimal), in the nose (nasal tone), or in the throat (breathy or pressed tone).
This may be because /ae/is farther away from the other two English sounds in the vowel space
and the Speaker finds it easier to distinguish them in terms of articulation.
The first variable is the acoustic vowel space
(AVS), which is the surface of the triangle formed by the F1 and F2 formant values of the vowels /i/, /u/, and /a/.
Catford (1988) talks about the concepts called "vowel space
" and "vowel limit".
Figures 20-22 show that the vowel space
is distributed identically for the male and the female speaker with higher formant frequencies for the female speaker as expected, given that women have a smaller vocal tract.
The classical model, especially the extremely well-known representation in terms of vowel space
devised by Luick (1964) (see Fig.
I intend to show and explain why there seems to be a smaller phonetic vowel space
in classical singing as opposed to normal speech.
Thus these vowels are `reference points' that can be used to describe the vowels of any language as these are `language neutral' (Ball and Rahilly 1999).Theoretically a vowel in any language must have tongue position either on the vowel limit itself or within the vowel space
The Lombard effect has been reported to cause measureable differences in vowel intensity and duration, and also in formant frequencies: ambient noise elevates the speech amplitude by 5-10 dB, increases word durations by 10-20%, and increases significantly the F1 and F2 frequencies, thus causing a shift in the vowel space
(van Summers, Pisoni, Bernacki, Pedlow, Stokes 1988; Castellanos, Benedi, Casacuberta 1996; Beckford Wassink, Wright, Franklin 2007).
The best-known proponent of this type of peripheral/nonperipheral distinction is probably Labov, for whom "[b]oth front and back vowel spaces
are divided into two regions of phonological space: a peripheral region, outside of the vowel space
, and a nonperipheral one, closer to the center" (1994: 32).
But it matters greatly: if it was already a kind of I, and there were two high tense vowels (say, [i:] and [iy]) in that vowel space
, then no chain shifting occurred of the type described by Labov, in which vowels maintain their distance and move like horses in tandem.