Phonology is the study of sound systems in language. It includes phonemes, which are the smallest units of sound that make a difference in meaning, as well as word stress, sentence stress, and intonation. Phonology examines features like vowels, consonants, voiced and unvoiced sounds, and word stress. It also considers how sounds are connected in speech. Functions refer to the reasons we communicate, such as apologizing, greeting, or advising. Exponents are the language used to express functions, and they can vary based on context and level of formality. Focusing on functions in language teaching emphasizes communication and helps give grammar meaning.