Aim To test the prediction of communication disorder severity at 5 years of age from characteristics at 2 years for children with cerebral palsy (CP) whose communication is giving cause for concern. Method In this cohort study, 77 children (52 males; 25 females) with communication difficulties and CP were visited at home at 2 (mean 2y 4mo; SD 3mo) and 5 (mean 5y 5mo; SD 4mo) years of age. Information on the type and distribution of motor disorder, seizures, gross and fine motor function, hearing, and vision were collected from medical notes. Non‐verbal cognition, language comprehension, language expression, spoken vocabulary, and methods of communication were assessed directly at age 2 years. At 5 years, communication and speech function were rated using the Communication Function Classification System (CFCS), Functional Communication Classification System (FCCS), and Viking Speech Scale (VSS). Results In multivariable regression models, CP type, Gross Motor Function Classification System level, vision, the amount of speech understood by strangers, non‐verbal cognition, and number of consonants produced at age 2 years predicted the CFCS level at age 5 years (R2=0.54). CP type, Manual Ability Classification System level, amount of speech understood, vision, and number of consonants predicted the FCCS level (R2=0.49). CP type, amount of speech understood by strangers, and number of consonants predicted the VSS level (R2=0.50). Interpretation Characteristics at 2 years of age predict communication and speech performance at 5 years, and should inform referral to speech and language therapy.