Preaspiration in the Nordic Languages: Synchronic and Diachronic ...

3.2.2 The perception of Icelandic preaspiration
As we saw in the preceding section, the ratio C/VC (or, equally,
V/VC) is relatively constant parameter in the production of VC sequences
in Icelandic. A series of experiments on the perception of preaspiration
in Icelandic have been carried out by Pind (see, e.g., 1986,
1993, 1995a, 1996a 1998). These experiments are part of a wider program
of establishing which factors underlie the perception of quantity in
Icelandic (cf., e.g., Pind 1986, 1995b, 1996b, 1996c). Pind (1986)
showed that the ratio V/VC, which indicates the relative contributions of
vowel and consonant in a VC sequence.
Pind (1993) suggested that the ratio Pr/VPr might provide a similarly
useful measure in the perception of preaspiration, since previous
durational measurements had shown that the Pr/VPr ratio was a relative
constant in speech production (e.g., Pind 1982). In one experiment, Pind
(1993; cf. also 1996a for similar findings) tested the perceptual threshold
of preaspiration in velar stops for Icelandic listeners. He prepared two
sets of vowel + stop stimuli, one with a total duration of 297 ms, and one
with 350 ms. In each set, 60% of the available duration was allotted to
VPr and the remaining 40% to O. Within each of the two sets, a new set
of 11 stimuli were created such that the contribution of Pr within VPr
varied in 11 increments between 0–64 ms. This yielded a total of 22
stimuli.
The results indicated a “phoneme boundary” between unaspirated
and preaspirated stops in Icelandic at 27.35 ms for the 297 ms stimuli,
and at 34.4 for the 350 ms stimuli. Thus the phoneme boundary shifts upwards
slightly as overall duration increases. However, viewed in terms of
the Pr/VPr ratio, there is far less difference in the phoneme boundaries.
For the 297 ms stimuli, the Pr/VPr ratio is 0.15 and for the 350 ms stimuli
it is 0.16. In terms of absolute durations, these results indicate that
preaspiration must be approximately 45–50 ms in duration for listeners to
be fairly sure that a stop is preaspirated at these long VPr durations. It is
likely that at shorter VPr durations, for example 150 ms, listeners will
still be evaluating the syllable in terms of Pr/VPr ratios and will thus
require a duration of perhaps only 25 ms to perceive the stop as preaspirated.
Such an experiment remains to be carried out, however.
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