Who is Sacagawea from The Journals of Lewis and Clark and what is their importance?

Sacagawea was Toussaint Charbonneau's wife. She was captured by the Hidatsa Indians when she was 12 years old. Charbonneau bought her from the Hidatsa tribe as a slave, he later married her, as well as another Shoshone captive.

Sacagawea was 16 years old and the mother of a young infant when she was hired as a Shoshone interpreter. She spoke neither French nor English, but she was fluent in Shoshone and Hidatsa. Charbonneau speaks only French and Hidatsa, yet he is the one actually hired as an interpreter.