A substitution error occurs when a speaker consistently replaces an intended phoneme with a different phoneme, altering the word’s pronunciation. These errors are common in children with speech sound disorders – for instance, a child might substitute an easier sound for a later-developing sound (such as using a front consonant like [t] for a back consonant [k], turning “cat” into “tat”). Unlike distortions (which produce an imprecise version of the correct sound), substitutions result in a clear change to a different phoneme, often affecting word meaning. Substitution errors are frequently observed in developmental articulation disorders and are a primary focus of therapy to establish correct sound production.
Jonathan Preston and Mary Louise Edwards. “Phonological Awareness and Types of Sound Errors in Preschoolers With Speech Sound Disorders.” Journal of Speech, Language, and Hearing Research 53, no. 1 (2010).
John E. Bernthal, Nicholas W. Bankson, and Peter Flipsen Jr. Articulation and Phonological Disorders: Speech Sound Disorders in Children. 8th ed. Pearson (2017).
