Supplementary Material for: A longitudinal investigation of oral inferential comprehension in French-speaking preschoolers: results from the ELLAN study

Introduction: Inferential comprehension is a complex language skill fundamental for social competence and reading comprehension. Evidence from the literature demonstrates that this ability develops early in a child’s life. Using a longitudinal design, this study aims to describe the early developmental trajectory of oral inferential comprehension ability in young typically developing French-speaking children from 3;6 to 5;6 years of age. Methods: A narrative-based oral inferential comprehension task was administered to a group of typically developing children (n=79) at 3;6, 4;6 and 5;6 years old; as part of the Early Longitudinal Language and Neglect [ELLAN] study. A total of 19 inferential questions were classified into six types of causal inferences targeting the comprehension of story grammar elements. Results: Inferential comprehension total scores showed significant improvement across all three time points, with the most significant increase between 3;6 and 4;6 years of age. At 3;6 years old, questions about the problem of the story, goal, and characters’ internal responses were better answered compared to questions about the attempts to solve the problem, predictions, and the story’s resolution. By 5;6 years of age, no ceiling effects were observed for any of the inference types, indicating ongoing development of inferential comprehension ability. Conclusion: Such longitudinal data documenting a developmental sequence of early oral inferential comprehension supports the importance of initiating assessments and interventions of this complex skill from an early age, especially from 3;6 to 4;6 years old, a period marked by significant growth.