By examining the four reprints of Robert Morrison’s Wuche yun fu (Five wagonloads of words) produced during the second half of the nineteenth century, this paper outlines the emergence and evolution of Chinese-English bilingual dictionaries and their role in spreading standard English to a wider literary audience in the treaty port of Shanghai. In the language mosaic of treaty port society, bilingual dictionaries highlighted the gap between spoken pidgin and written English, demarcating two linguistic repertoires commanded by two different groups. In exploring the socio-historical background of the publication history of these dictionaries, this paper also sheds light on the publishing market, especially English study aids in late nineteenth-century Shanghai.