Sulcalization

Sulcalization (from Latin sulcus, "groove"), in phonetics, is the pronunciation of a sound, typically a sibilant consonant, such as English and, with a deep groove running along the back of the tongue that focuses the airstream on the teeth, producing a more intense sound. That is accomplished by raising the sides of the back of the tongue ("lateral contraction") and leaving a hollow along the mid-line. It is not clear if all sibilants are so grooved: Catford (1977) observed that the degree of sulcalization differs between places of articulation as well as between languages, but no language is known to contrast a grooved and non-grooved sibilant.

English, which allows various tongue positions without apparent distinction, may also receive its characteristic quality from being sulcal.

In phonology and historical linguistics, sulcalization is the development of such a groove in a non-sulcal consonant. For example, close vowels trigger the effect in Japanese, in which historic *tu and *ti have become and, respectively. A similar sound changes as operated in the Senufo languages. (The palatalization of *tsi to in Japanese is a different process and does not occur in Senufo.)

Vowels may also be sulcalized, which has been described as giving them a "throaty" sound (Jones 1967:82). The vowel of Received Pronunciation, which is normally described as a rounded, is pronounced by some speakers without rounded lips for whom the characteristic quality is rather one of sulcality (Lass 1984:124).

One scholar has also suggested that the vowel in the RP pronunciation of words like bird, typically transcribed, is actually a sulcal schwa, retaining the sulcality of the original rhotic consonant. Accordingly, the realization of the -element of the centering diphthongs  in words such as near, pure and scare, is interpreted as the product of a loss of sulcality (Erickson 2003:197).