Infants' reliance on rhythm to distinguish languages: A critical review.

This article reviews empirical methods and findings on early language discrimination, questioning rhythm-class based hypotheses on language discrimination in infancy, as well as the assumption that early language discrimination is driven primarily (or solely) by temporal prosodic cues. The present work argues that within-rhythm class discrimination which - according to the rhythmic hypothesis - is not applicable very early in life, has not been sufficiently tested with infants under 4 months of age, that familiarity with a language is not a prerequisite for its discrimination from another rhythmically similar language, and that the temporal rhythm properties may not universally be the primary cues to language discrimination. Although rhythm taxonomy is now by many understood as outdated, some developmental literature still draws on the assumption that rhythm classification determines infants' language discrimination; other studies consider rhythm along a continuous scale and only a few account for cues to language discrimination other than temporal ones. It is proposed that studies on early language discrimination systematically test the contribution of other than temporal rhythm cues, similarly to recent work on multidimensional psychoacoustic salience in the acquisition of segmental categories.