Alveolar approximant

The alveolar approximant is a type of consonantal sound used in some spoken languages. The symbol in the International Phonetic Alphabet that represents dental, alveolar, and postalveolar approximants is ɹ, and the equivalent X-SAMPA symbol is r. The IPA symbol is a turned lowercase letter r. The segment is rare among the world's languages, and is sometimes called English R.

Some phonemic transcriptions use the symbol instead of <ɹ> for ease of typesetting, even though that former symbol technically represents the alveolar trill.

Features

Features of the alveolar approximant:

• Its manner of articulation is approximant, which means it is produced by bringing one articulator close to another but without the vocal tract being narrowed to such an extent that a turbulent airstream is produced.
• Its place of articulation is alveolar, which means it is articulated with either the tip or the blade of the tongue against the alveolar ridge, termed respectively apical and laminal.
• Its phonation type is voiced, which means the vocal cords are vibrating during the articulation.
• It is an oral consonant, which means air is allowed to escape through the mouth.
• It is a central consonant, which means it is produced by allowing the airstream to flow over the middle of the tongue, rather than the sides.
• The airstream mechanism is pulmonic egressive, which means it is articulated by pushing air out of the lungs and through the vocal tract, rather than from the glottis or the mouth.

Acoustically, the formants of [ɹ] are characterized by compressed f₁-f₃, particularly because of its low f₃ value. Its low f₃ values result from perturbations at three locations; rounded lips, alveolar constriction, and a constriction around the velum or pharynx. These constrictions cause perturbations at velocity maxima in the third harmonic of the voice signal, causing a sharp decrease in resonance frequency to below 1000 Hz.

Occurrence

See also

• List of phonetic topics
• velarized alveolar approximant