JOHANNESBURG, South Africa (AP) _ A 44-year-old linguist was sentenced Monday to 10 years in prison on a treason conviction for assisting the outlawed African National Congress guerrilla movement.

Helene Passtoors, a Dutch-Belgian citizen with four children, was sentenced by Justice Tjibbe Spoelstra in Transvaal Province Supreme Court. Spoelstra said Ms. Passtoors had acknowledged supporting the ANC, which he described as dedicated to the violent overthrow of the South African government.

Spoelstra said Ms. Passtoors helped set up arms caches for the group and also tried to arrange an escape from South Africa for an ANC member.

''This is conduct which no reasonable man nor a court of law can countenance,'' he said.

Ms. Passtoors is divorced from Klaas De Jonge, who was arrested with her last June. But De Jonge escaped from police and has been holed up since then in a Dutch Embassy office in Pretoria.

Spoelstra granted permission to appeal his finding that Ms. Passtoors owed allegiance to South Africa and thus could be convicted of treason. She had been in the country five months, attending graduate school, at the time of her arrest.

A treason conviction carries a maximum penalty of death in South Africa, but courts have issued this sentence only in cases where a defendant's actions have caused deaths.