Which term refers to the smallest unit of sound in speech?

The term that refers to the smallest unit of sound in speech is a phoneme. Phonemes are the individual sounds that make up spoken language. In any given language, rearranging phonemes can create different words and meanings. For instance, the words "bat" and "pat" differ only in their initial phonemes, showcasing how these small sound units play a crucial role in distinguishing one word from another.

Understanding phonemes is essential for literacy development, as they are foundational for phonics instruction. Children learn to recognize and manipulate these sounds when learning to read, which helps them to decode words and improve their reading skills.

The other terms have different meanings: graphemes refer to the written symbols representing phonemes, vowel digraphs are pairs of vowels that together make a single sound, and consonant clusters consist of two or more consonants that appear together in a word. Each of these plays a significant role in language, but they do not specifically denote the smallest unit of sound like a phoneme does.