Garze Tibetan Autonomous Prefecture and Ngawa Tibetan and Qiang Autonomous Prefecture in western Sichuan are populated by Tibetans and Qiang people. Tibetans speak the Khams and Amdo Tibetan, which are Tibetic languages, as well as various Qiangic languages. The Qiang speak Qiangic languages and often Tibetic languages as well. The Yi people of Liangshan Yi Autonomous Prefecture in southern Sichuan speak the Nuosu language, which is one of the Lolo-Burmese languages; Yi is written using the Yi script, a syllabary standardized in 1974. The Southwest University for Nationalities has one of China's most prominent Tibetology departments, and the Southwest Minorities Publishing House prints literature in minority languages. In the minority inhabited regions of Sichuan, there is bi-lingual signage and public school instruction in non-Mandarin minority languages.

Answer this question, if possible (if impossible, reply "unanswerable"): In what year was the language of the Yi people standardized?
1974