What does an 18-year-old college student have in common with a 90-year-old real-estate broker? A Washington psychiatrist with a gifted student from Loudoun County? A Washington economist with an Australian woman who has sailed around the world?

They all speak Esperanto.

Esperanto ("one who hopes") is the only specially-formulated international auxiliary language used throughout the world. It was invented by Dr. L. L. Zamenhof, a Polish doctor and linguist, who published the first book on Esperanto in 1887 under the pen name of Dr. Esperanto.

About 15 million people in over 80 countries speak some Esperanto and about 1 million people speak it fluently. It is not very well-known among Americans: In one recent poll of college students, only 4 per cent of college freshmen had heard of it.

One who has is self-taught Esperantist David Shaw, an 18-year-old college student from Reston. "Esperanto is the language of world peace," he says, "which has opened up communication around the world. I don't think it is going to disappear."

Shaw, who has always been fascinated with linguistics, learned Esperanto as a high-school sophomore. "Here was a language that I could pick up in just a matter of weeks. It's the easiest foreign language to learn because it has no irregularities in verbs, the vocabulary is easy and it's very logically put together.It's not a grandiose effort for anyone to undertake." l

Real-estate broker Lewis Maury, 90, became interested in the language in 1908 and is probably the oldest Esperantist in the Washington area. A former president of the New York Esperanto Society and the Washington Esperanto Society, he has corresponded in the language with people from all over the world.

Says Affonso Correa of Arlington, current president of The Esperanto Society of Washington, "The more you study Esperanto, the more you appreciate Zamenhof, the creator. It is not necessary to study it that hard to appreciate it."

"You could get as far with one year of Esperanto as with four or five years of French or Spanish," says Washington psychiatrist E. James Lieberman. "Esperanto does take a degree of commitment and you can become a semi-fluent reader or speaker in about three months."

Lieberman became enthusiastic about learning Esperanto while traveling in Europe as a student in 1954. He met people in France and Yugoslavia who spoke it, and he obtained a book on Esperanto which he brought back to the United States. He joined both the American and world organizations of Esperanto and was president of the Esperanto League for North America from 1972 to 1975.

"Some people have compared Esperanto with Yiddish because Yiddish is an international language without a mother country," says Lieberman. "Esperanto doesn't belong to any country. It is politically and psychologically neutral."

"Esperanto has no cultural identity and there is no stereotypical Esperantist," says Jimmie Osburn of Silver Spring, a data-processing consultant who has spoken Esperanto for four years.

"It's a tool of communication between diverse people. Esperanto enables you to converse with people from all over the world with virtually no language problem. It will never really die because some people approach it on almost a religious basis."

Says Rep. Paul Simon (D-Ill.), a former member of the President's Commission on Foreign Language and International Studies, "I believe in any tool that allows people to communicate across cultures because misperceptions of other nations lie behind many of the international disputes that we face today.

"Insofar as Esperanto becomes accepted by the general public in many countries, it will prove a facilitator of international contact and understanding."

On the future of Esperanto, Humphrey Tonkin, president of The Universal Esperanto Association, envisions the use of Esperanto by the United Nations. Another goal is to promote Esperanto as a regular subject in the schools. He maintains that students also could be introduced to other languages through Esperanto.

Esperanto is currently being taught as part of a program for 6th-, 7th- and 8th-grade gifted and talented students at Seneca Ridge Middle School, Sterling Middle School, Simpson Middle School and Blue Ridge Middle School in Loudoun County.

Gail Martin and Pat Beckner coteach this 9-week, 15-hour course, in which children learn how to read and write Esperanto. They also do such things as make up an imaginary country where Esperantists would live and discuss what they would look like and what kind of clothes they would wear. Other projects include making up Christmas cards, Valentine's Day cards and a beginning Esperanto reader.

Martin regards Esperanto as a steppingstone to learning another foreign language. "It has no irregularities," she says, "and it's easy to make a transition into French or Spanish."