phonology, study of the sound systems of languages. It is distinguished from phonetics, which is the study of the production, perception, and physical properties of speech sounds; phonology attempts to account for how they are combined, organized, and convey meaning in particular languages. Only a fraction of the sounds humans can articulate is found in any particular language. For example, English lacks the click sounds common to many languages of S Africa, while the sound th often poses problems for people learning English. Also, possible combinations of sounds vary widely from language to language—the combination kt at the beginning of a word, for example, would be impossible in some languages but is unexceptional in Greek. In phonology, speech sounds are analyzed into phonemes, the smallest units of sound that can change the meaning of a word. A phoneme may have several allophones, related sounds that are distinct but do not change the meaning of a word when they are interchanged. In English, l at the beginning of a word and l after a vowel are pronounced differently, so that the l in lit and the l in gold are allophones of the phoneme l; in other languages the difference between the two sounds could change the meaning of a word and so would be considered different phonemes.
See N. Chomsky and M. Halle, The Sound Pattern of English (1968); M. Kenstowicz and C. Kisseberth, Generative Phonology (1979); P. Hawkins, Introducing Phonology (1984).