Practice protocol! Learn foreign languages! Communicate with other countries!

Last week at a reception in the vast National Building Museum, Mayor Anthony Williams decreed Nov. 2 Diplomatic Community Day.

"Your embassies contribute not only to our local economy, but to the richness and diversity of our city," the mayor told the diplomatic guests, headed by Kingsley Cuthbert Augustine Layne, the St. Vincent and the Grenadines ambassador.

Williams announced the new observance with a proclamation, punctuated with a suitable number of "whereases":

"Washington is proud of its unique international character and the innumerable contributions made by its diplomatic community and other international residents," he said.

"In spite of the differences in our countries of origin, languages and cultures, we share the common goals of furthering international communication, cooperation and understanding. . . . This occasion provides a welcome opportunity to acknowledge and honor the contributions of those dedicated public servants who represent their countries here in our nation's capital."

Williams went on to say he wanted "stronger ties between the embassies and our neighborhoods. . . . There is a tremendous opportunity for cultural exchange and shared learning." In a brief commercial for the city, he brought up the opportunities for international business.

Lauren Manley, the mayor's assistant for protocol and international affairs, said the District government will do more to help the embassies to solve their local problems. Williams himself promised both home folk and diplomats that he is working to restore basic services for everyone--"clearing roads in winter and making streets to be safe."

The mayor and his wife, Diane Simmons Williams, introduced the evening's guests to parts of Washington and its history by standing at the second-floor entrance to the museum's splendid permanent exhibition of Washington history and neighborhoods. The Williamses greeted numerous foreign ambassadors and other diplomats posted in Washington, including those of Cyprus, Lithuania, Laos, Nepal, France and Germany.

They also greeted such worldly Washington citizens as John Hechinger, whose collection of art made of or about tools also is on exhibit at the Building Museum; Rep. Constance Morella (R-Md.); a delegation from the State Department; and Lee McGrath, Didi Cutler and others on the mayor's advisory committee on protocol. Janet Howard and Michael Goltzman represented the evening's sponsor, Coca-Cola. A suitable number of hard-working waiters passed among the crowd with delicacies, wine and, of course, Coke.

Susan Henshaw Jones, the museum president, and Janet S. Curtis, its vice president for development, said the museum plans to revamp the 1991 installation, the only exhibit in Washington that tells the history of the development of the nation's capital.

The enlarged show will include models, architectural drawings, fragments and photos, as well as interactive computer terminals. It tells a "compelling story of this city--a city of monuments and neighborhoods." In a 3,000-square-foot first-floor gallery, the federal core of the city will form the center of the exhibit and the surrounding areas will represent the city's quadrants, with the displays of neighborhoods changing periodically.

All of this is estimated to cost $580,000, of which two-thirds has been raised. An unnamed benefactor has agreed to match gifts of $1,000 or more. The exhibit is unlikely to be reinstalled until next year.

Ruth A. Davis, a career diplomat who served as ambassador to Benin and consul general in Barcelona, as well as in other posts in Africa, Asia and Europe, spoke about her experiences. She is credited with helping bring the 1996 Olympic Games to Atlanta and is a recipient of a presidential distinguished diplomatic service award. She's now director of the Foreign Service Institute at the State Department.

Davis counseled the diplomatic corps that there are many Washingtons: the Washingtons of the State Department, Capitol Hill, international events such as the NATO Summit, the Supreme Court, the business world, the arts--including the Kennedy Center, the Smithsonian Institution, the Corcoran Gallery. Then she cited "the Washington of the average resident, the blue-collar worker, the white-collar worker, government workers." And finally, "international Washington, in which the diplomatic community plays such a principal role."

As he was approaching the end of his speech, the mayor said, "I want to be brief, and I want to be concise, and I want to be seated."

CAPTION: "Embassies contribute . . . to the richness and diversity of our city," said Mayor Anthony Williams.