The various Indigenous nations of the Columbia Plateau and the Snake River country each had their own language or languages.

The voyageur workforce spoke French as its primary language of inter-community communication.

American traders and trappers spoke English.

The trade itself generated a set of specialized vocabulary and pidgin forms that allowed communication across linguistic boundaries.

Marie’s ability to function in this environment was not a passive capacity.

It required active command of multiple linguistic registers: her native Ioway, some degree of Sioux-related languages (through her relationship with Pierre, whose mother was Sioux), French (the language of the voyageur culture), and likely some familiarity with the Sahaptin-language family of the Columbia Plateau that included the Walla Walla, Nez Perce, and related peoples.

The fact that her sons knew to call out in French when they saw Franchère’s brigade on the Columbia River indicates the linguistic environment in which Marie had raised them: French was the language that would most reliably be understood by fur-trade personnel, and her boys knew this.