Developmental Aspects of Formant Frequency and Bandwidth in Infants and Toddlers

Abstract

Average formant frequency and formant bandwidth values are reported in a cross-sectional sample of 20 children between 4 and 25 months of age. With the exception of a slight rise in F₁ at 18 months of age, average F₁ and F₂ values changed little during the time period, while the average bandwidths for F₁ (B₁) and F₂ (B₂) were found to significantly decrease as age increased. The pattern observed for both average formant frequencies and formant bandwidths were attributed to developmental reconfiguration of the vocal tract.

Developmental and cross-linguistic variation in the infant vowel space: The case of Canadian English and Canadian French

“…Our findings of a decrease in formant frequencies with age is not consistent with the earlier findings of Gilbert et al ͑1997͒ andRobb et al ͑1997͒ who found that F1 and F2 remained stable across age. This difference in findings across studies may be accounted for by utterance selection.…”

“…In addition to being consistent with previous findings ͑e.g., Buhr, 1980;Gilbert et al, 1997;Kent and Murray, 1982;Robb et al, 1997;Rvachew et al, 1996͒, these changes are a predictable consequence of developmental changes in the infant's ability to control tongue tip, tongue body, and tongue dorsum position, independently of jaw height, as indicated by the simulations reported in experiment 2 and shown in Table I, when comparing the limited and full range simulations.…”

“…The acoustic characteristics of vowels produced by English-learning infants have been described in a number of prior studies ͑Buhr, 1980; Gilbert et al, 1997;Kent and Murray, 1982;Robb et al, 1997;Rvachew et al 1996;Sussman et al 1999;. These studies have revealed a strong preference for central vowels, with very little developmental change in the location of the center of the vowel space, and a very gradual expansion of the range of vowels produced with age.…”

“…A small reduction of the mean F2 was observed during the latter half of the observation period. Robb et al ͑1997͒ described the vowels produced by 20 children aged 4 to 25 months in a cross-sectional study. Contrary to expectations, no decrease with age in mean F2 or F1 was apparent.…”

“…This difference in findings across studies may be accounted for by utterance selection. In their papers, Gilbert et al ͑1997͒ andRobb et al ͑1997͒ acknowledge that possible changes in F1 and F2 may have been obscured by nasal resonance in the younger children's vocalizations. In the present study we controlled for this by only analyzing vowels with normal phonation and full resonance.…”