phonology
n//foʊ-//fonologi
(uncountable) The study of the way sounds function in languages, including accent, intonation, phonemes, stress, and syllable structure, and which sounds are distinctive units within a language; (countable) the way sounds function within a given language; a phonological system. [from late 18th c.]
(by extension, uncountable) The study of the way components of signs function in a sign language, and which components are distinctive units within the language; (countable) the way components of signs function within a given sign language.