Duration and spectral balance of intervocalic consonants: A case for efficient communication

The prosodic structure of speech and the redundancy of words can significantly strengthen or weaken segmental articulation. This paper investigates the acoustic effects of lexical stress, intra-word location, and predictability on sentence internal intervocalic consonants from accented words, using meaningful reading materials from 4157 sentences read by two American English speakers. Consonant duration and spectral balance in such reading materials show reduction in unstressed consonants and in consonants occurring later in the word (Initial vs. Medial vs. Final). Coronal consonants behaved distinctly, which was interpreted as a shift from full to flap or tap articulation in a subset of the phoneme realizations. This shift in articulation, and part of the consonant specific acoustic variation, could be linked to the frequency distribution of consonant classes over the investigated conditions. A higher frequency of occurrence of a consonant class in our corpus and a CELEX word-list was associated with shorter durations and differences in spectral balance that would increase the communicative efficiency of speech.