Phonology is part of linguistics. Linguistics is the scientific study of language. Phonology is the science that studies the way that sounds (phones) carry meaning in language. Sounds (phones) that carry meaning in language are called phonemes. Sounds that do not carry meaning in the language are called allophones.
Phonology focuses on the study of phonemes, "units of sound (speech) that distinguish one word from another in a particular language." Phonology also includes studies of how words are articulated, or spoken.
Phonology refers to the sound patterns of a language. Phonology is different from phonetics. Phonology studies how sounds form meaning in language. Phonetics studies how those sounds are formed. Studies of phonology and phonetics are sometimes combined, which results in more specific areas of study.
In 300 BC, Panini was the first person to study phonology. He created a grammar (a set of language rules) for Sanskrit (an ancient Indian language). He also created a list of the phonemes in Sanskrit. He assigned a symbol to represent each phoneme. The symbols are still used today in phonology.
The first person to use the word "phoneme" was the French linguist (one who studies language) A. Dufriche-Desgenettes. In the 1800s, Jan Baudoin gave the definition of phoneme that is uses today.Soon afterward, Baudouin de Courtenay began the study of phonology.and worked on the theory of phonetic alternations, which predicts changes in the sounds of a language.
One of the best schools of phonology was the Prague school. In 1939, a student of that school, Prince Nikolai Trubetzkoy, published one of the most important studies on phonology. His work was titled Principles of Phonology. Another important person in the Prague school was Roman Jakobson. Roman was the most well-known linguist in the 1900s.
In 1968, Noam Chomsky and Morris Halle published The Sound Pattern of English (SPE). This book described generative phonology, which studies how grammar changes how people use language.