During the occupation, the Japanese had their language taught in schools, and Government officers were required to learn Japanese. The local currency was replaced by what was to become known as ''duit pisang'' (banana money). From 1943 hyper-inflation destroyed the currency's value and, at the end of the war, this currency was worthless. Allied attacks on shipping eventually caused trade to cease. Food and medicine fell into short supply, and the population suffered famine and disease.