The Contribution of Functional Load on Children's Vocalic Development

Abstract

Children's phonology is replete with regular, predictable phenomena that nevertheless differ from adults. Discrepancies between adult and child speech cannot solely be attributed to environmental input, so immature motor development is often cited. Normally-developing children quickly acquire the motor skills and segment planning necessary to avoid these "errors." But phonological development continues well into late-childhood. For example, age and segment duration/variability are negatively correlated in English and French. Here we present contradictory data from Chuquisaca Quechua that show children producing shorter vowel durations than adults and attribute this to the role of functional load (FL). Interest in FL as an explanatory device for phoneme merger and segment inventories has recently resurfaced, but extension of the metric to phonological acquisition has been limited. FL is an important concept to apply to children's speech development because children's relatively smaller lexicons may lead them to make different generalizations regarding the relative importance of certain phonological contrasts. We test this hypothesis in Chuquisaca Quechua, a language where we predict maximal distinctiveness between adult and child lexica due to the language's morphological structure. We find that FL addresses this developmental pattern in the children's vowels.