Oh there is indeed a backstory.  I envisaged Oda to be a wild frontierswoman, who like her historical analogues in the American West and, perhaps more relevantly to this setting, the Urals and Siberia, learned native languages and cultures, admiring their mastery of their environment. Plus, it gets lonely out in the wilderness and linguists will tell you that the best way to learn a foreign language is full immersion with native speakers...