Purpose: The authors sought to describe longitudinal changes in Percentage of Consonants Correct--Revised (PCC-R) after severe pediatric traumatic brain injury (TBI), to compare the odds of normal-range PCC-R in children injured at older and younger ages, and to correlate predictor variables and PCC-R outcomes. Method: In 56 children injured between age 1 month and 11 years, PCC-R was calculated over 12 monthly sessions beginning when the child produced greater than or equal to 10 words. At each session, the authors compared odds of normal-range PCC-R in children injured at younger (less than or equal to 60 months) and older (greater than 60 months) ages. Correlations were calculated between final PCC-R and age at injury, injury mechanism, gender, maternal education, residence, treatment, Glasgow Coma Score, and intact brain volume. Results: PCC-Rs varied within and between children. Odds of normal-range PCC-R were significantly higher for the older than for the younger group at all sessions but the first; odds of normal-range PCC-R were 9 to 33 times higher in the older group in sessions 3 to 12. Age at injury was significantly correlated with final PCC-R. Conclusion: Over a 12-month period, severe TBI had more adverse effects for children whose ages placed them in the most intensive phase of PCC-R development than for children injured later. (Contains 3 tables and 3 figures.)