Discrimination and identification of a third formant frequency cue to place of articulation by young children and adults

Typically-developing children, 4 to 6 years of age, and adults participated in discrimination and identification speech perception tasks using a synthetic consonant-vowel continuum ranging from /da/ to /ga/. The seven-step synthetic /da/-/ga/ continuum was created by adjusting the first 40 ms of the third formant frequency transition. For the discrimination task, listeners participated in a Change/No-Change paradigm with four different stimuli compared to the endpoint-1 /da/ token. For the identification task, listeners labeled each token along the /da/-/ga/ continuum as either “DA” or “GA.” Results of the discrimination experiment showed that sensitivity to the third-formant transition cue improved for the adult listeners as the stimulus contrast increased, whereas the performance of the children remained poor across all stimulus comparisons. Results of the identification experiment support previous hypotheses of age-related differences in phonetic categorization. Results have implications for normative data on identification and discrimination tasks. These norms provide a metric against which children with auditory-based speech sound disorders can be compared. Furthermore, the results provide some insight into the developmental nature of categorical and non-categorical speech perception.