For the first time in 12 years, the International Phonetic Association is
amending its official alphabet. A sound called the labiodental flap will be
granted its own letter, one that looks something like a v with a hook.

The sound, a buzz sometimes capped by a faint pop, is present in more than
70 African languages. It is produced by the lower lip moving back and forward,
flapping on the inside of the upper teeth.

''The labiodental flap sound is as important as any other sound to speakers
of languages that use it,'' said Peter Ladefoged, emeritus professor of
linguistics at the University of California, Los Angeles. ''Think how Americans
would protest if there were no way of transcribing the vowel in 'bird,' which in
the usual U.S. pronunciation is almost as rare among the sounds of the world's
languages as the labiodental flap.''

Until now, linguists have recorded the sound with made-up symbols, usually
the letter v modified by accents. The venerable phonetic alphabet was
established in 1886, and now, after slow increments of change, includes 28
symbols for vowels, 86 for consonants and 75 other marks for tone, stress,
aspiration and other phonetic details.

One of the most recent sounds to win a symbol was the bilabial click, used
in two African languages. The labiodental flap is much more widely used but took
longer to be recognized.

One reason, said Dr. Ladefoged, is that clicks, often considered to be the
most exotic of speech sounds, have been noticed by Europeans since the 17th
century. They also occur in politically important languages like Zulu and Xhosa.

''None of this is true about labiodental flaps,'' Dr. Ladefoged said in an
e-mail message. ''Even now, some people think they are a minor effect in a few
words in a few languages.''

Last spring, he encouraged Kenneth S. Olson, a linguist at SIL
International who has studied the extensive use of the labiodental flap in
Africa, to propose officially that the sound, first observed in 1907, have its
own symbol.

SIL International is a Christian organization based in Dallas that studies,
documents and helps in developing lesser-known languages.

Dr. Olson encountered the sound while conducting research in Congo and had
performed extensive acoustic analysis to determine that the sound was, in fact,
a flap, not a fricative consonant like the ''f'' of English. Nor did it involve
a sharp intake of air like the clicks.

The new symbol had been recommended by a fellow linguist, Geoff Pullum, who
described it ''as if a fishhook R had been slammed leftward into a lowercase v
so hard its vertical had merged with the right leg of the v, and the dangly bit
had been left hanging there like the drain pipe out of an upstairs toilet in a
partially demolished building.''

In June, Dr. Olson received a note from the association, informing him that
the proposal had been voted on and accepted. Mono speakers are pleased, Dr.
Olson said. ''The idea of an I.P.A. symbol would offer some prestige to the
language, that this oddity is valued by people around the world.''

Other language oddities wait for their moment. There is a bilabial trill in
two Brazilian languages, Oro Win and Wari'
(phonetics.ucla.edu/appendix/languages/orowin/orowin.html) and what Dr.
Ladefoged called ''hissing-hushing fricatives'' of Ubykh, once spoken in Turkey
(phonetics.ucla.edu/appendix/languages/ubykh/ubykh.html).

Dr. Olson plans to visit the Philippines to study a sound that speakers
produce by sticking their tongues out of their mouths, a sound that outsiders
ridicule.

Dr. Olson says an official symbol might raise the status of the sound and
the people who pronounce it, though perhaps not with the symbol from rock 'n'
roll marketing he jokingly proposed -- the Rolling Stones' lips.