The development of spectral features in the speech of Indian children

Indian children represent a unique population of bilinguals who learn two or more languages of different isochrony. Most of their native languages are syllable-timed, whereas in school the language of learning is English, which is a stress-timed language. Exposure to multiple languages with different types of rhythmic patterns as stimulus during the development stage differentiates these children from monolinguals acquiring rhythms of a single language. Thus, to partially fill this gap, a comparative study in 115 children (aged four to eight years) and 18 adults was carried out. We investigated the frequencies around the pitch and first formant which encodes prosodic information in speech. It was found that the harmonic content in speech increases even after four years (where children exhibit or possess intelligent speech) and the spectra of adults were more distributed and had more peaks at higher frequencies as compared to the power spectra of children, where energy in higher frequency was less. This study has implications in finding speech abnormalities in Indian children with speech disorders.