Phonology

Phonology is the subfield of linguistics that studies the structure and systematic patterning of sound in human language.

A phoneme is a speech sound that is psychologically a single unit, in contrast with other such units. It is an abstract element, a set of phonological features (e.g., bilabial, stop) having several predictable manifestations (called allophones) in speech.

An allophone is a positional variant of a phoneme. Each allophone is the specific rule-governed and therefore predictable relaization of the phoneme in a particular linguistic environment. The allophones of the phoneme occur in complementary distribution or in free variation; they never contrast.

Minimal pairs are pairs of words that...

a) ... have the same number of phonemes.

b) ... differ in a single sound in a corresponding position in the two words, and ...

c) differ in meaning.

Complementary distribution is a relation between two (or more) speech sounds such that each occurs in one or more positions where the other one never does. Two (or more) sounds that are phonetically similar and that are in complementary distribution are usually allophones of the same phoneme.

Contrastive distribution is a relation between two (or more) speech sounds such that replacing one by the other sometimes makes a difference in the meaning of a word. Two (or more) sounds that are in contrastive distribution are allophones of different phonemes.

Free variation is a relation between two (or more) speech sounds such that either one can occur in a certain position, and the substitution of one for the other never makes any difference in the meaning of a word. Two (or more) sounds that phonetically similar and are in free variation are allophones of the same phoneme.

Assimilation is a rule that makes neighbouring segments more similar by copying or spreading a phonetic property from one segment to the other.

Dissimilation is a process by which one segment systematically avoids taking on a feature (or a set of features) of a neighboring segment.