Acknowledgments

I am grateful to several mentors for their education, advice, inspiration, encouragement, and friendship. Among various linguistic frameworks, the most useful include cognitive linguistics, functionalist linguistics, historical morphology and syntax, and particularly grammaticalization theory. During my graduate studies, I took courses and independent studies in grammaticalization theory with Elizabeth Traugott at Stanford University, in historical morphology and syntax with Paul Kiparsky at Stanford University, in cognitive linguistics with Ronald Langacker and Gilles Fauconnier at the University of California, San Diego, and in functionalist linguistics with Sandra Thompson at the University of California, Santa Barbara.

I owe a huge debt to my mentor and friend Charles N. Li, who introduced me to the field of Chinese historical linguistics. As a research fellow I joined the Historical Morpho-syntax of Chinese project, whose principal investigator was Charles N. Li, which was supported by the National Science Foundation of America, at the University of California, Santa Barbara, in 1996. This was the first time that I started to do research in Chinese historical linguistics. It was extremely fruitful, as we coauthored dozens of papers and one monograph that was published by Peking University Press in 2001.

I returned to Stanford University as a visiting scholar, with Paul Kiparsky as my mentor, in 2010–2011. In this academic year, I took many courses in linguistics, such as Laboratory Syntax, taught by Joan Bresnan; Linguistic Typology, taught by Paul Kiparsky; and Diachronic Construction Grammar and Constructionalization, taught by Elizabeth Closs Traugott, which were extremely helpful in studying the evolution of Chinese grammar. Additionally, I benefited greatly from personal communications with these professors.

Special thanks are due to Tania Kuteva. Her books are always inspiring for my research. More importantly, Tania played the key role in the publication of this manuscript by the prestigious Cambridge University Press. When she was invited to deliver a lecture at National University of Singapore in 2018, Tania recommended my manuscript to the press and offered critical help during every stage of the publication process. Moreover, Tania graciously provided excellent comments and suggestions on an earlier version of this manuscript, which were extremely helpful in improving the quality of this book.

I am grateful to Professor Tan Eng Chye, the president of National University of Singapore, for giving me generous aid when my family suffered a tragedy, which helped me concentrate on my research and teaching. I am indebted to National University of Singapore for affording me a wonderful working environment. In the past two decades, I have been invited to give talks about historical Chinese linguistics by numerous universities and conferences in mainland China, Japan, South Korea, Canada, and the USA, where I benefited greatly from the audiences.

Over the years, I have collaborated with many colleagues to carry out research. I would like to take this chance to express my appreciation for them, including Charles N. Li, Audrey Li, Li Chongxing, and Wang Tongshang.

I have been fortunate beyond words to have enjoyed the love, support, wisdom, and laughter of my daughter, Crystal. Finally, my deepest gratitude goes to my parents and sisters, Shi Li (my elder sister), Yupu (my younger sister), Yuluo (my younger sister), and Yuhong (my youngest sister), who managed to take pride and pleasure in my work even though it has meant time away from them. They have all made my dream come true.