Quantifying the sonority hierarchy
A long-standing controversy in the interface between phonetics and phonology involves the nature of sonority. This dissertation seeks to help resolve this problem by showing that the sonority hierarchy is both physically and psychologically real. This is accomplished by reporting the results of two rigorous and in-depth experiments. The first of these involves phonetic (instrumental) measurements of five acoustic and aerodynamic correlates of sonority in English and Spanish: intensity, frequency of the first formant, total segmental duration, peak intraoral air pressure, and combined oral plus nasal air flow. Intensity values are found to consistently yield a correlation of at least .97 with typical sonority indices. Consequently, sonority is best defined in terms of a linear regression equation derived from the observed intensity results.
The second major experiment—this one psycholinguistic in nature—involves a common process of playful reduplication in English. A list of 99 hypothetical rhyming pairs such as roshy-toshy was evaluated by 332 native speakers. Their task was to judge which order sounds more natural, e.g., roshy-toshy or toshy-roshy. The data again confirm the crucial importance of sonority in accounting for the observed results. Specifically, the unmarked (preferred) pattern is for the morpheme beginning with the more sonorous segment in each pair to occur in absolute word-initial position. A generalized version of the Syllable Contact Law is utilized in the formal analysis of this phenomenon in terms of Optimality Theory. Finally, a complete and universal sonority hierarchy is posited by building on the findings of the two experiments as a whole.