unlike chinese, nôm was not studied or classified systematically for most of its history. vietnamese authors who had studied chinese applied the principles of chinese writing to their native language. although official records were generally kept in chinese, nôm was used under two short-lived dynasties, the ho dynasty (1400-1407) and the tay son (1778–1802). king minh mang (1820-1841) opposed literacy and the use of nôm. in 1838, jean-louis taberd wrote a nôm dictionary that eventually gained general acceptance and wide circulation. in 1867, catholic scholar nguyen truong to petitioned king tu duc to replace classical chinese with nôm in official usage. the king did not consent to this, but he did respond with various efforts to promote nôm. a decree was issued entitled "please respect "quốc âm" [the national voice]."