Perception of Lexical Stress in Developmental Dyslexia: Evidence from an Identification Experiment in Italian

The perception of lexical stress and its acoustic correlates plays is crucial for language acquisition and processing. Previous research has suggested that deficits in the perception and/or phonological representation of lexical stress may constitute one of the core issues in developmental dyslexia (DD) – disordered acquisition of reading and writing. However, evidence remains mixed. Alternative proposals suggest that poor performance on typical stress perception tasks may reflect neither perceptual nor phonological deficits as it arises from a reduced metacognitive skill required under an increased cognitive load of a complex perception task. The present study investigated the perception of lexical stress in Italian-speaking children with and without an official diagnosis of DD using an identification task designed to minimize metacognitive demands. Fifty-seven children aged 8-10 years participated in the study. Participants listened to five 7-step continua manipulated in pitch, duration, rise-time, intensity, or all cues combined. Their task was to categorize the perception of each stimulus as either papa /ˈpapa/ ("pope") or papà /paˈpa/ ("dad") by choosing the corresponding picture on the screen. The results showed no significant differences between the two participant groups in either identification responses or reaction times, indicating that all children were equally able to use pitch and duration (but not amplitude rise-time and intensity) as reliable acoustic-prosodic cues to lexical stress in the non-metacognitive task. These findings support the cognitive load hypothesis of lexical stress perception in DD and suggest that empirical study of speech prosody ought to be sensitive to the multi-component nature of prosodic competence.