 Classifiers did not gain official recognition as a lexical category (part of speech) until the 20th century. The earliest modern text to discuss classifiers and their use was Ma Jianzhong's 1898 Ma's Basic Principles for Writing Clearly (马氏文通). From then until the 1940s, linguists such as Ma, Wang Li, and Li Jinxi treated classifiers as just a type of noun that "expresses a quantity". Lü Shuxiang was the first to treat them as a separate category, calling them "unit words" (单位词 dānwèicí) in his 1940s Outline of Chinese Grammar (中国文法要略) and finally "measure words" (量词 liàngcí) in Grammar Studies (语法学习). He made this separation based on the fact that classifiers were semantically bleached, and that they can be used directly with a number, whereas true nouns need to have a measure word added before they can be used with a number. After this time, other names were also proposed for classifiers: Gao Mingkai called them "noun helper words" (助名词 zhùmíngcí), Lu Wangdao "counting markers" (计标 jìbiāo), and Japanese linguist Miyawaki Kennosuke called them "accompanying words" (陪伴词 péibàncí). In the Draft Plan for a System of Teaching Chinese Grammar (暂拟汉语教学语法系统) adopted by the People's Republic of China in 1954, Lü's "measure words" (量词 liàngcí) was adopted as the official name for classifiers in China. This remains the most common term in use today.
