An acoustic description of consonant reduction1
The acoustic consequences of the articulatory reduction of consonants remain largely unknown. Much more is known about acoustic vowel reduction. Whether the acoustical and perceptual consequences of articulatory consonant reduction are comparable in kind and extent to the consequences of vowel reduction is still an open question. In this study we compare acoustic data for 791 VCV realizations, containing 17 Dutch intervocalic consonants and 13 vowels, extracted from read speech from a single male speaker, to otherwise identical segments isolated from spontaneous speech. Five acoustic correlates of reduction were studied. Acoustic tracers of articulation were based on F2 slope differences and locus equations. Speech effort was assessed by measuring duration, spectral balance, and the intervocalic sound energy difference of consonants. On a global level, it shows that consonants reduce acoustically like vowels on all investigated accounts when the speaking style becomes informal or syllables become unstressed. Methods that are sensitive to speech effort proved to be more reliable indicators of reduction than F2 based measures. On a more detailed level there are differences related to the type of consonant. The acoustic results suggest that articulatory reduction will decrease the intelligibility of consonants and vowels in comparable ways.
speech effort spectral balance acoustic consonant reduction speech style