Voiceless dental fricative

The voiceless dental non-sibilant fricative is a type of consonantal sound used in some spoken languages. It is familiar to English speakers as the 'th' in thing. Though rather rare as a phoneme in the world's inventory of languages, it is encountered in some of the most widespread and influential (see below). The symbol in the International Phonetic Alphabet that represents this sound is ⟨θ⟩, and the equivalent X-SAMPA symbol is T. The IPA symbol is the Greek letter theta, which is used for this sound in Greek, and the sound is thus often referred to as "theta".

The dental fricatives are often called "interdental" because they are often produced with the tongue between the upper and lower teeth, and not just against the back of the upper teeth, as they are with other dental consonants.

Among the more than 60 languages with over 10 million speakers, only English, Standard Arabic, Castilian Spanish (i.e., as spoken in Spain only), Burmese, and Greek have the voiceless dental fricative. Speakers of languages and dialects without the sound sometimes have difficulty producing or distinguishing it from similar sounds, especially if they have had no chance to acquire it in childhood, and typically replace it with a voiceless alveolar fricative, voiceless dental plosive, or a voiceless labiodental fricative (known respectively as th-alveolarization,^[1] th-stopping,^[2] and th-fronting.^[3])

The sound is known to have disappeared from a number of languages, e.g. from most of the Germanic languages or dialects, where it is retained only in English and Icelandic.

Features

Features of the voiceless dental fricative:

• Its manner of articulation is fricative, which means it is produced by constricting air flow through a narrow channel at the place of articulation, causing turbulence. It does not have the grooved tongue and directed airflow, or the high frequencies, of a sibilant.
• Its place of articulation is dental which means it is articulated with the tongue at either the upper or lower teeth, or both. (Most stops and liquids described as dental are actually denti-alveolar.)
• Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
• It is an oral consonant, which means air is allowed to escape through the mouth only.
• It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
• The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.

Occurrence

Voiceless alveolar non-sibilant fricative

The voiceless alveolar non-sibilant fricative (also known as "slit" fricatives) is a consonantal sound. As the International Phonetic Alphabet does not have separate symbols for the alveolar consonants (the same symbol is used for all coronal places of articulation that aren't palatalized), this sound is usually represented by <θ̠>, <θ͇> (retracted or alveolarized θ, respectively), or <ɹ̝̊> (constricted voiceless ɹ).

Features

• Its manner of articulation is fricative, which means it is produced by constricting air flow through a narrow channel at the place of articulation, causing turbulence. However, it does not have the grooved tongue and directed airflow, or the high frequencies, of a sibilant.
• Its place of articulation is alveolar, which means it is articulated with either the tip or the blade of the tongue at the alveolar ridge, termed respectively apical and laminal.
• Its phonation is voiceless, which means it is produced without vibrations of the vocal cords. In some languages the vocal cords are actively separated, so it is always voiceless; in others the cords are lax, so that it may take on the voicing of adjacent sounds.
• It is an oral consonant, which means air is allowed to escape through the mouth only.
• It is a central consonant, which means it is produced by directing the airstream along the center of the tongue, rather than to the sides.
• The airstream mechanism is pulmonic, which means it is articulated by pushing air solely with the lungs and diaphragm, as in most sounds.

Occurrence

See also

• List of phonetics topics
• Pronunciation of English th

References

Bibliography

• Hickey, Raymond (1984), "Coronal Segments in Irish English", Journal of Linguistics 20 (2): 233–250, doi:10.1017/S0022226700013876 
• Marotta, Giovanna; Barth, Marlen (2005), "Acoustic and sociolingustic aspects of lenition in Liverpool English", Studi Linguistici e Filologici Online 3 (2): 377–413, http://www.humnet.unipi.it/slifo/2005vol2/Marotta-Barth3.2.pdf 
• Martínez-Celdrán, Eugenio; Fernández-Planas, Ana Ma.; Carrera-Sabaté, Josefina (2003), "Castilian Spanish", Journal of the International Phonetic Association 33 (2): 255–259, doi:10.1017/S0025100303001373 
• Thelwall, Robin (1990), "Illustrations of the IPA: Arabic", Journal of the International Phonetic Association 20 (2): 37–41 
• Wells, John C (1982), Accents of English, second, Cambridge: Cambridge University Press, ISBN 0-521-24224-X 

External links

• Discrimination of Unvoiced Fricatives using Machine Learning Methods