Articulate sound

In phonetics and phonology, articulation is the movement of the tongue, lips, jaw, and other speech organs (the articulators) in ways that make speech sounds.

Sound is produced simply by expelling air from the lungs. However, to vary the sound quality in a way useful for speaking, two speech organs normally move towards each other to contact each other to create an obstruction that shapes the air in a particular fashion. The point of maximum obstruction is called the place of articulation, and the way the obstruction forms and releases is the manner of articulation. For example, when making a p sound, the lips come together tightly, blocking the air momentarily and causing a buildup of air pressure. The lips then release suddenly, causing a burst of sound. The place of articulation of this sound is therefore called bilabial, and the manner is called stop (also known as a plosive).

Articulation can be shown with magnetic resonance imaging to demonstrate how the tongue, lips and jaw move and the rise and fall of the soft palate. Such movement alters resonant properties of the vocal tract, and imposes a "time-varying formant structure" onto the speech signal. The study of articulation in making speech is called articulatory phonetics.

An obstruction is necessarily formed when two articulators come close together. Generally, one is moving (the active articulator), and the other is stationary (the passive articulator). As a result, what is normally termed the "place of articulation" is actually a combination of a place of active articulation and a place of passive articulation. For example, the English f sound is labiodental—a shorthand way of saying that the active articulator is the lower lip, which moves up (along with the jaw in general) to contact the upper teeth. The lower lip can also be the active articulator for other places of articulation (e.g. bilabial, where it contacts the upper lip, as in English p). Likewise, the upper teeth can be the passive articulator for other places of articulation (e.g. dental, where the tongue contacts the upper teeth, as in the English th sound).

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