A guided tour through the powerful poetry of Langston Hughes

The Dream Keeper Speaks: The World of Langston Hughes Performance piece based on poems of Langston Hughes. Starring John S. Patterson. Directed by Ernest Parham. When actor John S. Patterson populates the teeming world of black poet Langston Hughes, the occasion is more than a tribute to a treasured literary legacy. It's an adventure, a vivid guided tour through earlier decades of the black experience in America and the irrepressible folk who animated it.

The entertainment is called ''The Dream Keeper Speaks: The World of Langston Hughes.'' According to Mr. Patterson, this digest of some 80 pieces represents ''the first full treatment of Hughes's poetry since he stopped touring colleges and universities giving poetry readings in the '60s.'' From the moment he delivers the observations of a young black American in a white teacher's writing class, Mr. Patterson draws the spectator into the poet's world. It is a world where art and creativity coexist with the struggle for recognition and even survival.

Mr. Patterson's way with the poems heightens their effectiveness as brief chronicles, playlets from recent and bygone racial history. When the bitterness of blighted dreams is called for - as in the early political and protest poems - Mr. Patterson can summon the anger and frustration the writing demands. But even bitterness over injustice and inequality can come out with ironic humor. And a piece like ''An Advertisement for the Waldorf Astoria'' combines stinging social comment with a hilarious sense of the ridiculous. Mr. Patterson responds with fierce relish as he peruses the glossy ad, item by item.

West Indian emigres mingle with Harlem natives as Patterson-Hughes tours the precinct, taking a kind of lyric census of the people, noting their tribulations and joys. There are poems about everyday life and everyday death, crime and drugs and family life, dances and parades, poverty and unemployment. Hughes's concern embraces South African blacks as well as Afro-Americans. One poem asks, ''Where is the Jim Crow car on the merry-go-round?'' But the means are personal and human rather than didactic. Mr. Patterson serves as Hughes's alter ego and as the portrayer of a numerous cast.

''The Dream Keeper . . .'' exults above all in the joy and laughter that were such an essential part of the spirit of Langston Hughes. ''Harlem Sweeties'' is an ecstatic tone poem. ''When Susanna Jones Wears Red'' is full of zest and sparkle. Mr. Patterson also delves generously into the ''Madam'' poems in which Hughes dramatized the boisterous life and times of Alberta K. Johnson, whose ''K.'' stood for plain and simple ''K.'' (not ''Kay'').

Mr. Patterson is now in the course of an extensive tour, which has included performances in New York City and Orangeburg, South Carolina. He is currently appearing for the Berkeley Stage Company, Berkeley, Calif., through Dec. 11. Thereafter, his itinerary will be as follows: New Orleans junior high schools (Jan. 9-24); New York's Schomberg Collection (Feb. 1) and American Museum of Natural History (Feb. 3); University of Rochester, Rochester, N.Y., (Feb. 3); Onondaga Community College, Syracuse, N.Y., (Feb. 6); Mary Holmes College, West Point, Miss., (Feb. 16); Tougaloo College, Tougaloo, Miss., (Feb. 19).

''The Dream Keeper'' is a show worth watching for.