Which term describes the act of replacing one sound with another in speech?

The term that accurately describes the act of replacing one sound with another in speech is substitution. This phenomenon occurs when a speaker alters a particular sound in a word with a different sound, resulting in a variation of that word. For instance, a child might say "wabbit" instead of "rabbit," where the /r/ sound is substituted with a /w/ sound.

Understanding substitution is crucial in the study of communication disorders, as it can provide insights into a speaker's phonological development and any potential speech difficulties they may be experiencing. This knowledge can inform the types of interventions or therapies that may be necessary to support the individual in achieving clearer speech.

Other terms like reduction, elision, and assimilation refer to different processes in speech sound modification. Reduction involves simplifying sounds or syllable structures, elision refers to the omission of sounds, and assimilation describes the process where a sound changes to become more like a neighboring sound. These concepts, while related to speech sound patterns, do not specifically indicate the replacement of one sound with another as substitution does.