Acoustic and spectral characteristics of young children’s fricative productions: A developmental perspective

Abstract

Scientists have made great strides toward understanding the mechanisms of speech production and perception. However, the complex relationships between the acoustic structures of speech and the resulting psychological percepts have yet to be fully and adequately explained, especially in speech produced by younger children. Thus, this study examined the acoustic structure of voiceless fricatives (/f, theta, s, S/) produced by adults and typically developing children from 3 to 6 years of age in terms of multiple acoustic parameters (durations, normalized amplitude, spectral slope, and spectral moments). It was found that the acoustic parameters of spectral slope and variance (commonly excluded from previous studies of child speech) were important acoustic parameters in the differentiation and classification of the voiceless fricatives, with spectral variance being the only measure to separate all four places of articulation. It was further shown that the sibilant contrast between /s/ and /S/ was less distinguished in children than adults, characterized by a dramatic change in several spectral parameters at approximately five years of age. Discriminant analysis revealed evidence that classification models based on adult data were sensitive to these spectral differences in the five-year-old age group.

Production of contrast between sibilant fricatives by children with cochlear implants

“…First, in children with NH, there is a protracted period of acquisition of the contrast between /s/ and /$/ (Nittrouer et al, 1989;Nittrouer, 1995;Nissen and Fox, 2005;Li et al, 2009). This finding suggests that speaking and listening experience play a role in the development of this contrast.…”

Spectral dynamics of sibilant fricatives are contrastive and language specific

“…Yet, a number of studies, using only static spectral measures, have sought to characterize the development of a child's productive knowledge of how a phonological sibilant contrast is implemented phonetically (e.g., Fox and Nissen, 2005;Li, 2012;Li et al, 2009;McGowan and Nittrouer, 1988;Nissen and Fox, 2005;Nittrouer et al, 1989;Romeo et al, 2013). Since the spectral patterns that must be acquired and produced by a language learner are dynamic in nature, the view of acquisition provided by static measures is likely incomplete.…”

Acoustic characteristics of clearly spoken English fricatives

“…Parameters that seem to influence identification include gross spectral shapes and peak frequencies ͑Behrens and Blumstein, 1988;Hughes and Halle, 1956;Jongman et al, 2000;Strevens, 1960͒, the first four moments of the spectral energy distribution ͑Forrest et Jongman et al, 2000;Nissen and Fox, 2005;Nittrouer, 1995;Nittrouer et al, 1989;Shadle and Mair, 1996͒, the slopes of lines fitted to spectra in lower and higher frequency regions ͑Evers et Jesus andShadle, 2002͒, formant transition information ͑Jongman et al, 2000;McGowan and Nittrouer, 1988;Nittrouer et al, 1989;Soli, 1981͒, overall amplitude ͑Beh-rens andBlumstein, 1988;Jongman et al, 2000;Stevens, 1971;Strevens, 1960͒, amplitude relative to the neighboring vowel in specific frequency regions ͑Hedrick and Ohde, 1993;Jongman et al, 2000;Stevens, 1985͒, andduration ͑Baum andBlumstein, 1987;Crystal and House, 1988;Jongman, 1989;Jongman et al, 2000͒. Briefly, alveolar fricatives ͑/s/, /z/͒ are characterized by spectral energy ͓above 4 kHz, Hughes and Halle ͑1956͔͒ and major peaks ͓3.5-5 kHz, Behrens and Blumstein ͑1988͒; 6 -8 kHz, Jongman et al ͑2000͔͒ at higher frequencies compared to palato-alveolars ͑/b/, /c/; 2 -4 kHz; ͓Hughes and Halle ͑1956͒, Behrens and Blumstein ͑1988͔͒, which display larger overall relative amplitudes.…”