UCL
Working Papers in Linguistics 16 (2004)
Vowel reduction as information loss
JOHN HARRIS
Vowel reduction suppresses phonetic information in the speech
signal and should be understood as having an analogous impact on phonological
representations.
Reduction follows two
apparently contradictory routes in vowel space, yielding either centralised values (the ‘centripetal’ pattern)
or the corner values a, i,
u (the ‘centrifugal’ pattern). What
unifies these vowels is the relative simplicity of their acoustic spectra compared
to those of mid peripheral vowels. Spectral complexity can be taken as one measure
of the amount of phonetic information present in a speech signal at a given
time. On this basis, centripetal and centrifugal reduction can both be
construed as resulting in a loss of phonetic information.
In selectively targeting
non-prominent positions, reduction has the effect of enhancing syntagmatic contrasts among vowels. Representing vowels in
terms of three basic components manifested as a,
i and u allows informational
asymmetries of this sort are to be directly recorded in phonological grammars.
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