UNITED NATIONS -- The United Nations building would be little more than a glass Tower of Babel without them.
But the United Nations' core of interpreters, who sit tucked away in badly ventilated glass booths overlooking the General Assembly hall, are to most delegates little more than disembodied voices that come piped in through white plastic earphones.
"We are all performers at heart," said Monique Corvington, who has worked as an interpreter since 1968. "We get stage fright and the rush of adrenaline. Unfortunately, we do not pick the script."
The United Nations Interpretation Service has been sorely tested of late by the crush of world leaders who have shown up here for the General Assembly session and the recent World Summit for Children, which was attended by more than 70 heads of state and government.
The service had to bolster its normal complement of 130 full-time interpreters with 70 free-lance interpreters, including two retirees who did simultaneous interpretation at the Nuremberg war-crimes trial.
The technique of simultaneous interpretation -- interpretation sentence by sentence -- got its start at Nuremberg, translators here said.
It proved much faster than the old system of consecutive interpretation, in which successive interpreters, after taking copious notes, redelivered the original speech in different languages.
The Nazi leader Hermann Goering reportedly said simultaneous translation at Nuremberg shortened his remaining life by three-fourths.
The interpreters here work in the six official languages of the United Nations -- English, Russian, Chinese, French, Spanish and Arabic -- out of a ground-floor office overlooking the East River.
Performing mental gymnastics, they have seconds to search for the correct phrase or word and must take expressions or proverbs that have no meaning if they are literally interpreted -- like "raining cats and dogs" -- and find an equivalent expression.
"Quotations from the Bible or the Koran are dreadful," said Claudia Bishop, a French national who grew up in Mexico and can move with equal facility between French and Spanish, a rare commodity in the world of simultaneous interpretation. "You just can't do a good rendering off the cuff."
"The worst are puns, since they are based on a play of words in one language," said Barbara Roder, another interpreter, an American citizen who was born in Romania, grew up in Mexico and was educated in French.
Many of the interpreters -- and they will thank you kindly never to refer to them as translators, who deal only with written texts -- have lived or traveled in several countries outside their native lands.
"We are a mini-United Nations," said Mrs. Corvington, a Haitian who grew up in Europe and who interprets from Spanish, English and Italian into French. "We have all sorts of nationalities and all sorts of languages."
The starting salary for a United Nations interpreter is about $30,000 and climbs to about $60,000 for a senior interpreter.
Minimum qualifications for a U.N. interpreter are a college degree and the ability to interpret from two foreign languages into the interpreter's mother tongue.
Interpreters are required to pass an oral examination, in which they interpret two 10-minute speeches from their two foreign languages.
Native Russian and Chinese interpreters are sent over by their foreign ministries for fixed periods of time.
They are not allowed to make a career at the United Nations, although the Soviets now say that this arrangement is under review.
The Chinese require staff members to make reports on United Nations activities, and both the Soviets and the Chinese frequently make their interpreters and translators go to the mission to do extra, unpaid work, according to complaints submitted to the union by Chinese and Soviet staff members.
Union officials said the Chinese and Soviet employees must also turn 40 percent of their salaries over to their governments.
Inevitably the interpreters, because of linguistic confusion or the enormous pressure, make some mistakes.
Mrs. Corvington once had to translate an anecdote from Spanish into French about a German shepherd who saved the life of a little boy.
The Spanish words for German shepherd, "pastor aleman," can also mean a German cleric.
"I told how the German minister dove into the water to save the child, swam to the child's rescue and then let out a loud bark when he got back to the shore," Mrs. Corvington said.
Translators, especially when they get tired, sometimes find themselves slipping in spoonerisms. Jeannette Morrison, a 16-year-veteran, said she once found herself calling Secretary General Javier Perez de Cuellar, Cuerez de Pellar.
There are also times when the interpreters find themselves fighting back their own emotions to carry out their work.
"When you have to relate stories of torture or suffering it can get difficult," said Frederic Siegenthaler, who once struggled to interpret the emotional appeal of a torture victim as he broke down in tears and had to be carried from the room.
A few years ago an interpreter who survived the Holocaust had to interpret the vitriolic anti-Semitic statements of an Iraqi delegate.
"I remember having to say that most of the owners of the brothels in New York City were Jewish," said this interpreter, who insisted that she not be identified.
"The words nearly stuck in my throat, but I did it."
After one lengthy peroration that many in the booths above the hall found particularly repugnant, an interpreter, thinking her microphone was switched off, turned to her colleague and said, "Cretin."
The word wafted out over the headsets to the stunned delegates below.