Sam Pollard (missionary) in the context of Weining Yi, Hui, and Miao Autonomous County

The Yi scripts (Yi: ꆈꌠꁱꂷ, romanized: nuosu bburma; Chinese: 彝文; pinyin: Yí wén) are two scripts used to write the Yi languages; Classical Yi (an ideogram script), and the later Yi syllabary. The script is historically known in Chinese as Cuan Wen (Chinese: 爨文; pinyin: Cuàn wén) or Wei Shu (simplified Chinese: 韪书; traditional Chinese: 韙書; pinyin: Wéi shū) and various other names (夷字、倮語、倮倮文、畢摩文), among them "tadpole writing" (蝌蚪文).

This is to be distinguished from romanized Yi (彝文羅馬拼音 Yíwén Luómǎ pīnyīn) which was a system (or systems) invented by missionaries and intermittently used afterwards by some government institutions (and still used outside Sichuan province for non-Nuosu Yi languages, but adapted from the standard Han Pinyin system and used to romanize another syllabary based on a subset of simplified Han ideograms). There was also the alphasyllabary (or abugida) devised by Sam Pollard, the Pollard script for the Miao language spoken in Yunnan province, which he adapted for the Nasu language as well. Present day traditional Yi writing can be sub-divided into five main varieties (Huáng Jiànmíng 1993); Nuosu (the prestige form of the Yi language centred on the Liangshan area), Nasu (including the Wusa), Nisu (Southern Yi), Sani (撒尼) and Azhe (阿哲).

The Pollard script, also known as Pollard Miao (Chinese: 柏格理苗文; pinyin: Bó Gélǐ Miáo-wén) or Miao, is an abugida loosely based on the Latin alphabet and invented by Methodist missionary Sam Pollard. Pollard invented the script for use with A-Hmao, one of several Miao languages spoken in China. The script underwent a series of revisions until 1936, when a translation of the New Testament was published using it.

Pollard credited the basic idea of the script to the Cree syllabics designed by James Evans in 1838–1841: "While working out the problem, we remembered the case of the syllabics used by a Methodist missionary among the Indians of North America, and resolved to do as he had done." He also gave credit to a Chinese pastor: "Stephen Lee assisted me very ably in this matter, and at last we arrived at a system."