2 The author uses a word that means "doubtful" in the text. Circle a word in the paragraph that best represents that idea. The Navajo code was proposed by a non-Navajo, Philip Johnston, the son of missionaries on the reservation. Marine officers were skeptical at first. American armies had used other Indian languages to send messages during World War I. Yet because the ancient dialects had no words for machine gun or tank, the experiment failed. Johnston had a better idea―a language combined with a code....