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R.J.J.H.
van Son and Louis C.W. Pols
Institute
of Phonetic Sciences/IFOTT
University
of Amsterdam
Herengracht
338, 1016 CG Amsterdam, The Netherlands
tel:
+31 20 5252183; fax: +31 20 5252197; email: {rob, pols}@fon.hum.uva.nl
ABSTRACT
It
is proposed that some of the variation in speech is the result of an effort to
communicate efficiently. Speaking is considered efficient if the speech sound
contains
only
the information needed to understand it. This efficiency is tested by means of
a corpus of spontaneous and matched read speech, and syllable, word, and N-gram
frequencies as measures of information content (1582 intervocalic consonants,
and 2540 vowels). It is indeed found that the duration and spectral reduction
of consonants and vowels from stressed syllables correlate with syllable and
word frequencies, as does consonant intelligibility. Correlations for phonemes
from unstressed syllables are generally weaker or absent. N-gram models of word
predictability did not correlate with any of the factors investigated. Simple
N-grams seem to be a poor model for human word prediction. It is concluded that
the principle of
efficient
communication
organizes at least some aspects of speech production.