Early Vocalizations as Predictors of Later Language Development in Preterm Infants: A Longitudinal Study from 12 to 24 Months

Objectives: Preterm infants are at increased risk for delayed language development. This study aimed to investigate the impact of vocalization at 12 months on language abilities at 24 months in preterm infants and to assess whether early vocalization can serve as a predictor of later language outcomes.Methods: A longitudinal study was conducted with 31 preterm infants assessed at 12 and 24 months. At 12 months, vocalizations were evaluated via a caregiver interview tool and categorized into precanonical, canonical, and word stages, with percentage scores calculated for each. At 24 months, receptive and expressive language quotients were measured using standardized assessments.Results: Preterm infants demonstrated the highest scores in the precanonical stage at 12 months, with lower scores in the canonical and word stages. The canonical vocalization scores at 12 months were significantly correlated with receptive and expressive language quotients at 24 months, while precanonical vocalizations showed no significant correlations. Additionally, canonical vocalization scores significantly predicted expressive language abilities at 24 months. However, subcomponents of the canonical stage did not individually predict language outcomes.Conclusion: Canonical vocalization at 12 months is closely associated with expressive language development at 24 months in preterm infants. Early assessment of vocalization may be a useful tool for identifying infants at risk for language delays, enabling timely intervention.