Phonology: The study of language sound systems. Phonologists are concerned with questions such as: …What sounds contrast in one language but not another (answers to such questions explain why Spanish speakers have trouble with the difference between English sh and ch, or why English speakers have trouble with the different “u” sounds in French words like rue ‘street’ and roue ‘wheel’.)? …What sounds of a language can or cannot occur one after the other (for example, why can words begin in st- in English but not in Spanish)? ...How do poets or writers or song lyrics intuitively know how to match the rhythm of speech to the abstract rhythmic pattern of a poetic or musical meter?