This chapter introduces the development and application of multimodal SI corpora, using ECTSIC-P—the corpus specifically constructed for this study—as an illustrative example. Section 3.1 discusses the background of developing multimodal SI corpora. Section 3.2 details the development process. Section 3.3 first discusses the potential applications of multimodal SI corpora in interpreting research and then presents the overall research design and methodology of this study, specifically based on the ECTSIC-P corpus. Section 3.4 proposes a cognitive process analytical framework developed from the pilot studies of this research, serving as the primary methodology for the qualitative analysis in this book.