2 authors: Eman Awni Ali University of Jordan 7

Introduction

Despite the fact that discourse markers have been analyzed widely since the 1970s, there is still an ongoing controversy between researchers, adopting different or even similar theoretical frameworks, about the nature of these mysterious expressions. Accordingly, the researchers who study these expressions do not agree on the characteristics, classifications, functions, core meanings, definitions or even labels under which they are to be analyzed. For example, Fraser (1999) refers to these expressions as discourse makers; Blakemore (1987) labels them as discourse connectives; Halliday and Hasan (1976) identify them as sentence connectives whereas Redeker (1990) refers to them as discourse operators.
Furthermore, various definitions have been proposed to account for the nature and functions of these linguistic items. Redeker (1991, p.1168), for instance, defines a discourse operator as an expression which is equipped “with the primary function of bringing to the listener's attention a particular kind of linkage of the upcoming utterance with the immediately preceding discourse context.” Another definition is proposed by Schiffrin (1987, p.31) who defines these markers as “sequentially dependent elements that bracket units of talk.” Maschler (1994, p.325) defines discourse markers (henceforth DMs) as “a subcategory of metalingual expressions: those used to mark boundaries of continuous discourse.” Moreover, a number of researchers such as Schiffrin (1987) argue that some DMs have a core meaning while others (e.g. interjections) lack any meaning without explicitly defining the nature of this meaning. Contrary to Blakemore (1987) who claims that DMs have only procedural meaning, Fraser (2009, p.16) argues that DMs potentially have “both conceptual and procedural meaning, though not in equal proportions.”
In spite of the researchers' disagreement about many aspects of DMs, they typically agree on three main characteristics that define the nature of these devices. Connectivity is approved to be one of the necessary conditions of discourse markers by many researchers. For example, Schiffrin (1987) claims that DMs contribute to the local coherence of a discourse by signaling connections between two adjacent textual units, while Fraser (2009) argues that DMs can contribute to local and global coherence. Discourse markers are also believed to contribute nothing to the truth conditionality of the linguistic segments that they connect and this can lead to another characteristic of these markers which is their optionality (e.g. Brinton, 1996; Fung, 2003; Muller, 2005).

The heterogeneity of the syntactic classes from which they are drawn, detachability of clause syntactic structure and initiality are also commonly recognized characteristics of DMs (Schourup, 1999).

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