Developmental courses of infants' articulations estimated by acoustic-to-articulatory inversions

Abstract

Knowledge about the actual movements of articulators and their developmental changes in early childhood is crucial to a better understanding of the relationship between speech productions and perceptions. In this study, we attempted to recover the shapes of articulators from the acoustic properties of infants' vocalizations by using a variable linear articulatory model (Boe, 1999). We randomly selected 30 samples of 5 Japanese vowels at three age groups (8, 24, and 50 months) from the NTT Japanese infants speech database (Amano etal., 2002) and those pronounced by adults. We modeled shapes of articulators and size of the vocal tract according to Maeda (1990) and synthesized vowels by forward transformation from the vocal tract cross-sectional area function to its acoustics. We performed inverse estimations of articulatory parameters from acoustic properties by using a pseudo-inverse of the Jacobian matrix. Statistical analysis of the estimated articulatory parameters revealed that the shapes of articulato...