Peer-reviewed article

Latent Classes of Typical and Atypical Speech Development in Low-Income Children: A Longitudinal Study From Early Childhood to Adolescence.

Liu Q, Tumanova V, Razza RA · 9 Jul 2026

Abstract

Purpose This study aimed to identify distinct latent classes of speech development by differentiating typical and atypical developmental trajectories from early childhood through adolescence in children from low-income families. It also examined demographic predictors of these latent classes and explored their associations with early infant temperament. Method We used five waves of longitudinal data from the Future of Families and Child Wellbeing Study, with families from low-income backgrounds below 200% of the federal poverty line (N = 2,802). First, we conducted a longitudinal latent class analysis (LLCA) on six indicators of speech problems and stuttering reported by mothers at 3, 5, 9, and 15 years of age. Second, we examined demographic predictors to distinguish longitudinal latent class membership. Third, we assessed early infant temperament to predict longitudinal latent class membership. Results LLCA identified three distinct speech development classes: typical speech development (n = 2,383, 85%); speech problem, not stuttering (n = 322, 11.5%); and persistent stuttering (n = 97, 3.5%). Compared to the typical speech development class, boys had a higher likelihood of belonging to the speech problem, not stuttering class or the persistent stuttering class. Children in the speech problem, not stuttering class exhibited greater levels of emotionality than did children in the typical speech development class. Conclusion Findings highlight the need for early identification and intervention for low-income children at risk of early speech problems and the necessity to adopt comprehensive and multilayer intervention across developmental transition stages.