[2] Zhengzhang was born as Zheng Xiangfang (郑祥芳 Zhèng Xiángfāng) in Yongjia County, on the outskirts of Wenzhou.
[3] At this time, he became interested in historical phonology and studied the works of Yuen Ren Chao, Wang Li and others at Wenzhou's library.
[3] In his spare time, he continued to develop his own ideas on Old Chinese phonology, particularly the finals and vowel system.
During a period when the factory was closed due to a factional battle in the Chinese Communist Party, he began exchanging ideas with Pan Wuyun and Jin Shengrong, and refined his Old Chinese system to a six-vowel system.
[5] Essentially the same system was independently developed by William Baxter (building on a proposal by Nicholas Bodman) and by Sergei Starostin.