What defines a phoneme?

• A. The largest unit of sound in a language
• B. A combination of letters that forms a word
• C. The smallest unit of sound that can distinguish one word from another
• D. An entire sentence structure

Answer: (C)

A phoneme is defined as the smallest unit of sound in a language that can distinguish one word from another. This means that changing a single phoneme in a word can result in a completely different meaning. For example, the words "bat" and "pat" differ by just one phoneme—the initial sound. This differentiation is essential for understanding spoken language, as phonemes form the basis of pronunciation and can substantially affect communication.

In contrast, the other choices refer to other linguistic concepts. The largest unit of sound in a language covers broader categories of speech sounds rather than the smallest distinguishing sound unit that phonemes represent. A combination of letters forming a word pertains more to graphemes and spelling rather than the actual spoken sound. Finally, an entire sentence structure does not pertain to sound units at all but instead involves grammar and syntax, completely separate from the concept of phonemes. Thus, defining a phoneme accurately underscores its role as a foundational element of language.