What is phonology?

Definition
	Phonology is the study of how sounds are organized and used in natural languages.

Discussion
	The phonological system of a language includes
	an inventory of sounds and their features, and rules which specify how sounds interact with each other.
	Phonology is just one of several aspects of language. It is related to other aspects such as phonetics, morphology, syntax, and pragmatics.
	Here is an illustration that shows the place of phonology in an interacting hierarchy of levels in linguistics:

Comparison: Phonology and phonetics

Phonetics … Phonology … Is the basis for phonological analysis. Is the basis for further work in morphology, syntax, discourse, and orthography design. Analyzes the production of all human speech sounds, regardless of language. Analyzes the sound patterns of a particular language by determining which phonetic sounds are significant, and explaining how these sounds are interpreted by the native speaker.

Models of phonology
	Different models of phonology contribute to our knowledge of phonological representations and processes:
	In classical phonemics, phonemes and their possible combinations are central. In standard generative phonology, distinctive features are central. A stream of speech is portrayed as linear sequence of discrete sound-segments. Each segment is composed of simultaneously occurring features. In non-linear models of phonology, a stream of speech is represented as multidimensional, not simply as a linear sequence of sound segments. These non-linear models grew out of generative phonology: autosegmental phonology metrical phonology lexical phonology