What is defined as a single unit of speech?

A phoneme is defined as a single unit of speech sound that distinguishes one word from another in a particular language. Phonemes are the basic building blocks of spoken language, representing the smallest sound units that can create differences in meaning. For example, the words "bat" and "pat" differ by just one phoneme, which alters their meanings entirely. Understanding phonemes is essential for grasping how speech sounds function in specific languages.

In contrast, a morpheme refers to the smallest grammatical unit in a language, which can be a word, a prefix, or a suffix, that carries meaning but is not purely a sound unit like a phoneme. A diphthong is a complex vowel sound that begins with one vowel sound and glides into another within the same syllable, showcasing the mixture of vowel sounds but not serving as a standalone unit of speech. A syllable is a larger unit that comprises a vowel sound or a combination of sounds, including consonants, and can consist of one or more phonemes. Thus, while all terms relate to aspects of speech, a phoneme specifically stands out as the single unit of speech.