The controversial U.S.-based Summer Institute of Linguistics, which translates the Bible into dialects in countries around the world, has been banned from carrying out further activities in Ecuador.

The institute is part of the Wycliffe Bible Translators with headquarters in Huntington Beach, Calif. It has been active among the Indians in Ecuador's eastern Amazon region since 1956, studying the native languages of remote tribes and transcribing them to written form.

A communique from the Ecuadoran president's office announcing the decision to expel the group said, "Wide sections of Ecuador's society have noted problems in how the institute conducted its affairs . . . regarding matters of national sovereignty and the preservation of aboriginal groups," and said the institute's work disrupted the development of the Indians along normal cultural lines.

The communique also said "it was necessary to regain control" of the eastern Amazon area, but did not elaborate.

The linguistic and social carried out by the institute will be taken over by various ministries, which will taken over the institute's facilities in about 12 months, the decree said.

The institute last came to international attention in March when one of its teachers, American Chester Allen Bitterman, was kidnaped and murdered by alleged leftist guerrillas in neighboring Columbia.

Ransom notes accused the institute of being a front for the CIA and demanded its departure from Columbia. The demands were not met. The institute has denied any ties to the CIA.