(1) A term used in the phrase source feature to refer to one of the five main dimensions of classification in Chomsky and Halle’s distinctive feature theory of phonology (the others being major class features, cavity features, manner-of-articulation features, and prosodic feature). The term subsumes the feature oppositions of heightened subglottal pressure, voice and strident.
(2) In acoustic phonetics, source refers to the waveform of the vibrating larynx. Its spectrum is rich in harmonics, which gradually decrease in amplitude as their frequency increases. The various resonance chambers of the vocal tract, especially the movements of the tongue and lips, then act on the laryngeal source in the manner of a filter, reinforcing certain harmonics relative to others. The combination of these two elements is known as the source-filter model of vowel production.
(3) In the study of communication, source refers to a point of origin of a message, as opposed to its ‘destination’. More specifically, in semantics, the term is used a s part of a localistic theory of meaning: an entity takes a ‘path’ from a ‘source’ to a ‘goal’. In case grammar, it refers to the place from which something moves.
(4) In historical linguistics, the term is used to characterize a language from which a particular feature (such as a loan word) comes (the ‘source language’); the receiving language is known as the ‘matrix’ language.
(5) In translating and interpreting, the term describes the language from which a message originates (the ‘source language’); the ‘target language’ is the one into which the translation takes place.