Full context:   Several languages, including Japanese and Lakota Sioux, use the same word to describe blue and green. For example, in Vietnamese, the colour of both tree leaves and the sky is xanh. In Japanese, the word for blue (青, ao) is often used for colours that English speakers would refer to as green, such as the colour of a traffic signal meaning "go". In Lakota, the word tȟó is used for both blue and green, the two colours not being distinguished in older Lakota (for more on this subject, see Blue–green distinction in language).