This chapter is concerned with what we know about the status and the history of discourse markers. The chapter provides a detailed discussion of the various hypotheses that have been proposed to account for the rise of discourse markers. It is argued that none of those hypotheses is entirely satisfactory, pointing out a number of shortcomings characterizing such earlier approaches. The conclusion reached in the chapter is that discourse markers exhibit a catalog of grammatical properties that are hard to explain on the basis of those approaches.

In this chapter, the framework proposed in Chapter 2 is applied to the history of English. The discourse markers studied are after all, anyway, I mean, if you like, if you will, instead, like, no doubt, right, so to say/so to speak, well, and what else. The findings presented are in support of the hypothesis proposed in Section 1.5, according to which discourse markers are the joint product of two separate mechanisms, with each of the mechanisms accounting for specific properties of discourse markers.

In this chapter, the framework proposed in Chapter 2 is applied to the history of French. The discourse markers studied are à la rigueur, à propos, à ce propos, alors, en fait, au fait, and enfin. The findings presented are in support of the hypothesis proposed in Section 1.5, according to which discourse markers are the joint product of two separate mechanisms, with each of the mechanisms accounting for specific properties of discourse markers.

In this chapter, the framework proposed in Chapter 2 is applied to the history of Korean. The discourse markers studied are icey, makilay, maliya, and tul. The findings presented are in support of the hypothesis proposed in Section 1.5, according to which discourse markers are the joint product of two separate mechanisms, with each of the mechanisms accounting for specific properties of discourse markers.

This chapter proposes a framework for analyzing the history of discourse markers. The framework rests, on the one hand, on the analysis of historical text data as they were provided in previous research. On the other hand, it proposes two contrasting mechanisms that need to be distinguished in order to reconstruct the rise and development of discourse markers. These mechanisms are grammaticalization and cooptation. It is via cooptation that discourse markers are transferred to the level of discourse management, thereby losing their status as constituents of a sentence, no longer being a part of the syntax, semantics, and frequently also of the prosodical form of sentences.

This chapter is reserved for issues that surfaced in previous chapters but for some reason or other could not be discussed there in any detail. On the one hand, the chapter looks at the framework outlined in Chapter 2 from a wider perspective. It is argued that the presence of two contrasting mechanisms is suggestive of a dual process model of the kind described in work on discourse analysis, neurolinguistics, and social psychology. On the other hand, the chapter shows that whereas the pathways leading to grammaticalization are highly constrained, those leading to the rise of discourse markers are almost unlimited. Further topics discussed in the chapter concern the structure of constituent anchored discourse markers and the role played by imperative forms in the rise of discourse markers. Finally, the chapter also looks into the role of a more marginal category of discourse-structuring devices, namely that of fillers or "hesitation markers."

The development of discourse markers is commonly believed to be a language-internal process. In this chapter it is demonstrated, however, that new discourse markers quite commonly also arise in situations of language contact. A range of borrowing processes are discussed, showing in particular that the borrowing process may extend across countries and continents. The Spanish discourse marker entonces "then, therefore, thus," for example, spread from Europe to Central and South America, Africa, and the Pacific Ocean area.

This chapter summarizes the findings presented in the book. As demonstrated in the preceding chapters, the rise of discourse markers is the result of a more complex process involving two separate mechanisms, namely grammaticalization and cooptation. It is argued that the framework used in the book offers an explanation of why discourse markers have the grammatical properties they do.

In this chapter, the framework proposed in Chapter 2 is applied to the history of Japanese. The discourse markers studied are dakedo, demo, douride, ga, jijitsu, sate, and wake. The findings presented are in support of the hypothesis proposed in Section 1.5, according to which discourse markers are the joint product of two separate mechanisms, with each of the mechanisms accounting for specific properties of discourse markers.