Probability estimates and paths to consonant normalization in children with speech delay.

Probable ages of normalization were calculated for 24 children with speech delay, using Kaplan-Meier analysis and a threshold score of 85% on the Percent of Consonants Correct, Percent of Consonants Correct-Adjusted, and Percent of Consonants Correct-Revised metrics. Simple formulas are provided that permit calculation of the likelihood that individual children with speech delay will normalize by a given age. The sex of a child was found to have no significant influence on age of normalization. Analysis revealed two different paths to normalization. In Path A, errors of deletion, substitution, and omission declined as correct productions increased. In Path B, common clinical distortions increased as deletions and substitutions decreased. The ages of more and less rapid phonological gain correspond to and partially explain the findings of Shriberg, Gruber, and Kwiatkowski (1994), who studied more severely involved children. Children who follow Path B are those who retain residual errors in their speech.