Chinese as a foreign or second language is when non-native speakers study Chinese varieties. The increased interest in China from those outside has led to a corresponding interest in the study of Standard Chinese as a foreign language, the official language of mainland China, Taiwan and Singapore. However, the teaching of Chinese both within and outside China is not a recent phenomenon. Westerners began learning different Chinese varieties in the 16th century. Within China, Mandarin became the official language in the early 20th century. Mandarin also became the official language of Taiwan when the Kuomintang took over control from Japan after World War II.