The Corporation Tuesday approved the appointment of 11 American journalists as 1978-79 Nieman Fellows, who will spend the academic year at Harvard auditing courses and holding off-the-record seminars with academicians, journalists and public officials.

An additional six or seven fellows from foreign countries will be named by September, James C. Thomson Jr., curator of the Nieman program, said yesterday.

Thomson said the fellowships provide an opportunity for early mid-career journalists to pursue subjects that they recognize they need to know, but would not otherwise have the time to study.

Nieman Fellows receive a stipend of $300 a week for 35 weeks. Fellows' spouses are treated as honorary fellows and are given all University privileges according to full fellows, Thomson said. The Nieman program also pays for child-care expenses, he added.

The 41st group of Niemans is: Sidney M. Cassese, assistant editor of Newsday; Nancy L. Day, regional editor of the San Francisco Examiner; Margaret A. Engel, government reporter for the Des Moines Register; William J. Gildea, reporter for The Washington Post; Katherine A. Harting, associate producer of ABC-TV News in Washington, D.C.; John C. Huff, city editor of The Greenville News; H. Victor Lewis, acting national editor of The Boston Globe; Robert M. Porterfield, reporter for the Anchorage Daily News; Peggy A. Simpson, congressional correspondent for the Associated Press; Frank A. Van Riper, Washington bureau correspondent for the New York Daily News; and Lawrence A. Walsh, managing editor of the Texas Observer.