Speech Categorization Consistency Predicts Overall Language Abilities

Studies on speech categorization have shown that trial-by-trial response variability is a crucial factor in characterizing speech categorization profiles over the mean slope of response functions. However, the relationship between this categorization consistency and general language function remains unknown. In Experiment 1, English-speaking adults (n=57) completed a Visual Analog Scaling (VAS) task, rating a speech continuum on a continuous scale, and two language assessments. Results showed that categorization consistency robustly predicted language scores, whereas slope did not. Experiment 2 (n=76) added a visual VAS task, rating images along a visual continuum, to examine whether speech VAS reflects broader differences in categorization. Results replicated Experiment 1, showing an even larger effect of speech categorization consistency. Commonality regression revealed that a large amount of the variance in language is uniquely due to speech categorization consistency. This suggests the robust association between speech categorization consistency and general language function.