The 11th Inter-American Festival got underway at the Kennedy Center last night with what was, strictly speaking, a North American program under the direction of Jorge Velazco. Two works from Mexico, which is also Velazco's home, were paired with Leonard Bernstein's Second Symphony.

The Bernstein piece is so brash, breezy, bright, bouncy and just plain brilliant that it can easily overshadow any companion works, and last night there was really no competition. The opening selection, "Lyhannh," by Mario Lavista, never got off the ground, sounding like an introduction to music that failed to make an appearance. Antonio Gomezanda's "Xiuhtzitzquilo," was pleasant, if rather simple, ballet music which badly needed some dancers to be effective.

Inspired by W.H. Auden's "The Age of Anxiety," Berstein's symphony translates into music the sense of restlessnes and insecurity which the poem explored. In some respects jazzy piano concerto, the symphony contains a highly inventive and fiendishly tricky piano part, which Bernstein himself played when the music was first introduced by the Boston symphony in 1949 under Serge Koussevitzky.

Last night the pianist was Lukas Foss, whose performance was illuminated by the most intimate understanding of every inflection and gesture in the Bernstein vocabulary. With compelling urgency Foss followed the symphony's shifting moods, from the moving, pensive solo with which the piano begins through the tightwire intricacies of the scherzo-like Masque movement.

Velazco's direction of the orchestra was competent but almost totally lacking in dynamism.