Thomas Ludwig's First Symphony, "Age of Victory," got a standing ovation last night at the Inter-American Music Festival. Such demonstrations happen a bit more often than they should these days in Washington, but this one was more deserved than most, and it was refreshing to see it given to a composer at a world premiere rather than a star soloist playing a favorite warhorse.

The audience was large for a concert devoted entirely to contemporary music--about three-quarters of the Kennedy Center Concert Hall's capacity. But this was not the celebrity-worshiping crowd that gives most standing ovations; it was basically the hard-core music lovers of Washington, people seen regularly at the Library of Congress and the Phillips Collection, and it included quite a few professional musicians. This kind of applause has some meaning.

Not that the Ludwig symphony is a dazzling revelation of new styles and techniques or a work of mature genius. It is a first symphony with the problems and promise proper to such work. Much of it is, in effect, a tribute to other composers from whom the beginner learned his craft--in this case, an honorable list that includes Beethoven, Tchaikovsky, Stravinsky, Shostakovich, Bernstein and John Corigliano (Ludwig's teacher, whose work includes the soundtrack for "Altered States").

The point is not that Ludwig speaks a language he learned from others. We all do that, musicians and non-musicians alike; Beethoven began by sounding like Mozart, who had begun by sounding like Johann Christian Bach. What matters is what is done with this shared language. In Ludwig's case, it is used eloquently by one who clearly has something to say and has mastered the grammar of musical structures, the vocabulary of motifs and orchestration. Above all, he communicated with the audience, which may have been applauding a return to communication in music as well as the work of a deserving local composer.

Communication was a motif throughout the evening, which opened with two evocative "Ambientes Sonoros" by Mexican composer Rodolfo Halffter (a teacher of conductor Jorge Velazco), and the world premiere of a piano concerto by German Caceres of El Salvador, who was recently featured as composer and oboe soloist in a concert at the Organization of American States.

Halffter presented two brief scenes--evening shadows darkening slowly into night, then a bright, brisk, busy sunrise with lots of brass and percussion. The Caceres concerto, played with good but not flashy technique by pianist Omar Mejia, is a work of considerable power whose modern flavor does not conceal a strong affinity for classic forms.

Velazco, conducting an orchestra of Washington free-lance musicians in totally unfamiliar music, was efficient and businesslike, with clear, precise gestures directed at the players, not at the audience. We need more conductors like him.