Nike, the shoe company, has come out with a television commercial for hiking shoes that was shot in Kenya using Samburu tribesmen. It combines broad shots of brightly clad, dancing men and women, and close-ups of the colorful new boots. There are no words until the very end. Then the camera closes in on the one tribesman who speaks, in native Maa. As he speaks, the Nike slogan, ''Just do it,'' appears on the screen.

Problem. Lee Cronk, an anthropologist at the University of Cincinnati, says the Kenyan is really saying: ''I don't want these. Give me big shoes.'' Nike admits its film crew improvised after having trouble getting a Maa version of the slogan. But, says Nike's Elizabeth Dolan, ''we thought nobody in America would know what he said.''

Just do what?