The rumbling of long stifled nationalism and democracy in the Soviet Baltics, Armenia and Ukraine has stirred new hope and activity among Americans who trace their origins to those republics.

For years Latvian Americans observed Latvian independence day and that was about it, says Ojars Kalnins. "Now there is a flood of tourists in both directions, phone calls, videos, letters. We are feeding off the euphoria over there."A video showing Latvians recently demonstrating in the streets of Riga, the capital, carrying the maroon and white national flag and chanting "God bless Latvia" brought tears to the eyes of those watching, said Kalnins, public relations director of the American Latvian Association.

"Young Latvian Americans are calling and asking where they can take Latvian lessons," said Kalnins. Many young people are visiting the land of their elders and return "full of pride in the old country and anger at seeing Soviet troops there."

Asta Banionis, of the Lithuanian-American Community Inc., said, "People are really excited" by news of rallies in Latvia this past summer and by tales of relatives visiting from the old country.

"Even the very conservative among us, who used to say, `What's the use?' are now optimistic when they see not merely a few dissidents speaking out but masses of people," she said. "It is a truly democratic movement. Now we know we weren't crazy all those years!"

Unprecedented numbers of Lithuanian Americans are inviting family members living in Latvia to visit them. Of the visitors, Banionis said, "Their expectations are high. They think Mikhail Gorba-chev is the best thing since sliced bread."

Mari-Ann Rikken of the Joint Baltic American National Committee similarly finds herself busy interpreting for visitors from Estonia, her parents' homeland.

In the minds of many Baltic Americans, the eventual separation of their family homelands from the USSR is an enduring hope.

At a White House meeting Friday between Reagan administration officials and Baltic American representatives, Rikken denounced as "an obscenity" one official's suggestion of sister cities linking Baltic and American communities. "They really don't know what it means that those nations are under Soviet military occupation," she said.

The Balts, she points out, have long histories and recent memories of national independence. Estonia, Latvia and Lithuania regained their independence from czarist Russia after World War I, only to be overrun and annexed by the Soviet Union during World War II.

The United States and about 30 other nations, including China and Yugoslavia, have never legally recognized Moscow's absorption of the Baltic states.

Thus there are Latvian and Lithuanian legations in Washington and an Estonian legation and consulate general in New York City, all duly recognized by the State Department and financed by gold reserves on deposit since the years of national independence.

Baltic Americans are pulling for their kinspeo-ple back home in their efforts to keep their language, preserve their culture and customs, stave off Russian colonization, and gain economic and political autonomy, Rikken said.

The current stirrings in the three Baltic republics have attracted international attention because Gorbachev has allowed and even encouraged nationalist and democratic expression as part of his drive for openness and modernization in the Soviet Union.

Said Kalnins, "The Balts are industrious, take pride in workmanship and are part of Europe. He wants to make them a model for a reformed Soviet Union. So he has to make them happier, but it's a balancing act. He can't let them go too far and he can't afford a total crackdown."

The Balts do not know how long Gorbachev's opening will last so they want to make the most of it.