was the only officially sanctioned medium of instruction in schools in Taiwan from late 1940s to late 1970s, following the handover of Taiwan to the government of the Republic of China in 1945, until English became a high school subject in the 1980s and local languages became a school subject in the 2000s. Taiwanese Mandarin (as with Singlish and many other situations of a creole speech community) is spoken at different levels according to the social class and situation of the speakers. Formal occasions call for the acrolectal level of Standard Chinese of Taiwan (), which differs little from the Standard Chinese of China (). Less formal situations may result in the basilect form, which has more uniquely Taiwanese features. Bilingual Taiwanese speakers may code-switch between Mandarin and Taiwanese, sometimes in the same sentence. Many Taiwanese, particularly the younger generations, speak Mandarin better than Hakka or Hokkien, and it has become a lingua franca for the island amongst the Chinese dialects. Taiwanese Hokkien Commonly known as Taiwanese (, ) and officially referred as Taiwanese Hokkien (); Taiwanese Hokkien is the most-spoken native language in Taiwan, spoken by about 70% of the population. Linguistically, it is a subgroup of Southern Min languages variety originating in southern Fujian province and is spoken by many overseas Chinese throughout Southeast Asia. There are both colloquial and literary registers of Taiwanese. Colloquial Taiwanese has roots in Old Chinese. Literary Taiwanese, which was originally developed in the 10th century in Fujian and based on Middle Chinese, was used at one time for formal writing, but is now largely extinct. Due to the era of Taiwan under Japanese rule, a large amount of loanwords from Japanese also appear in Taiwanese. The loanwords may be read in Kanji through Taiwanese pronunciation or simply use the Japanese pronunciation. These reasons makes the modern writing Taiwanese in a mixed script of traditional Chinese characters and Latin-based systems such as pe̍h-ōe-jī or the Taiwanese romanization system derived from pe̍h-ōe-jī in official use since 2006. Recent work by scholars such as Ekki Lu, Sakai Toru, and Lí Khîn-hoāⁿ (also known as Tavokan Khîn-hoāⁿ or Chin-An Li), based on former research by scholars such as Ông Io̍k-tek, has gone so far as to associate part of the basic vocabulary of the colloquial language with the Austronesian and Tai language families; however, such claims are not without controversy. Recently there has been a growing