Acoustic Variation among African American and European American Children: Age, Gender, and Ethnicity

Previous research shows that vowels are acoustically specified based on formant frequencies (Peterson & Barney, 1952). Their study was replicated and extended to include temporal and spectral measurements (Hillenbrand et al., 1995). While both studies included children, Peterson and Barney did not indicate age or gender, Hillenbrand et al. did not distinguish across gender, and neither study included data with respect to ethnicity. Therefore, more data is needed that provides the acoustic targets for children that take age, gender, and ethnicity into consideration. This study explores variations across age, gender, and ethnicity. There is a gradual lowering of the fundamental frequency of the voice beginning with the onset of puberty, which could begin as early as age 10 (Berger, 2008). This influences the phonological space, which could result in differences across gender, especially for the 11 to 12 year olds. Children recorded lists containing neutral consonantal context /h-vowel-d/ words and sentences. We hypothesize that fundamental and formant frequencies will be higher for 8 to 9 year olds than for 10 to 12 year olds and higher for girls (by age 10). With respect to ethnicity, we anticipate no significant differences in frequency measures between European-American and African-American children. We will present MANOVA results for age, gender, and ethnicity with temporal and spectral parameters. Additionally, we will report correlational analysis of height and weight with the acoustic measures. This study will contribute to our knowledge of developmental trajectories for specific acoustic parameters. As gender and ethnicity are vital cues for adult speakers, it is important to investigate how salient the acoustic parameters are for child speakers and at what ages the child parameters begin to approximate adult measures. Results will have implications for audiologists, speech language pathologists, developmental and speech scientists, and others in the field of communication sciences and disorders