The Okinawan language, the most widely spoken Ryukyuan language, is related to Japanese, the two being in the Japonic languages. Ryukyuan languages were heavily suppressed through a policy of forced assimilation throughout the former Ryukyu Kingdom after it was annexed in 1879. With only Japanese taught in schools and students punished for speaking or writing their native language through the use of dialect cards, the younger generations of Ryukyuans began to give up their "backwards" culture for that of Japan. The Japanese government officially labels the Ryukyuan languages as dialects (Hōgen) of Japanese, although they are not mutually intelligible with one another, or even between each other. In 1940, there was a political debate amongst Japanese leaders about whether or not to continue the oppression of the Ryukyuan languages, although the argument for assimilation prevailed. Japanese soldiers outright shot people who spoke Ryukyuan languages during the Battle of Okinawa, believing they were spies. There are still some children learning Ryukyuan languages natively, but this is rare, especially on mainland Okinawa. The language still is used in traditional cultural activities, such as folk music, or folk dance.