This module introduces grammaticalization, one of the approaches to historical linguistics, to graduate students. It focuses on topics of current interest, particularly the principles, the hypothesis of unidirectionality, the context and effects of grammaticalization, and the role of frequency. Chinese data will be examined or re-examined under the framework of grammaticalization. The similarities and differences between the theories of grammaticalization and lexicalization will also be discussed. This module is taught in Chinese.