8.2.2　Implications for the analytical tools for multimodal discourses

The genre analysis of the English learning advertisements reveals great complexity and hybridity in various aspects，such as the means of expression，structure，content，and communicative purpose.Therefore，any attempt to describe and analyze this genre in detail can only cover some aspects of it，rather than all.Discourse coherence provides an interesting point of departure for the exploration of this question.An analytical framework is proposed on the basis of the genre features of the English learning advertisements.The framework of coherence construction has significant meanings in the following aspects：

First of all，although some key distinctions in the research area of coherence have been proposed before，such as the distinction between coherence and cohesion，and the distinction between external and internal factors，there have been few comprehensive and operational frameworks which allow systematic description and analysis of the construction of discourse coherence.Most of the existing studies on coherence in purely verbal texts focus on only parts of these factors，especially the cohesive devices or the rhetorical and logical relations between sentences.In contrast，in this book，the resources and factors for the construction of coherence are systematically sorted into three categories：global coherence，local coherence and cohesion in layout.Global coherence means that the discourse topical structure forms the macro-control of all the semiotic elements in the whole discourse;the semantic connection between adjacent elements—local coherence，ensures that the segments of the discourse are related;while the cohesive devices in the realization level of discourse make the coherence relations easier to recognize for readers.The three levels often work simultaneously to form a coherent，well-organized representation of the discourse.The specific ways in which the three levels operate in the English learning advertisements are given in-depth analyses in Chapters 4，5，and 6.

Secondly，this book makes efforts to extend the notion of coherence to accommodate the complexity of semiotic representation in multimodal discourses such as the English learning advertisements under discussion.As Bateman（2008：8）recognizes，“the application of linguistic frames of analysis to multimodal artefacts is in fact neither selfevident nor obviously correct and so we need to proceed carefully”.This book agrees to this point and makes modifications to the definitions and working principles with considerations of the special features of multimodal discourses.For example，the cohesive devices in linguistic frames of analysis mainly refer to the lexical items which signal the logical relations between sentences.In multimodal discourses，however，the devices that mark the abstract logical relations are very limited，often implicit and unsystematic.With these considerations，a new working framework of cohesive devices in the layout is proposed in Chapter 6.In the analysis of local coherence，the semantic connection is also analyzed with a new means of indicator—information unit with which the cross-modal analysis between verbal meaning and visual meaning is made possible.

Thirdly，in addition to the systematic analysis of the coherence resources in the text，the framework is also proved to be valid in the reader's mental responses to the textual coherence construction.That is，the macro-control of discourse topic（global coherence），the semantic connection between adjacent elements（local coherence）and explicit cohesive devices（surface cohesion）are proved to work on the reader's cognitive processes when he reads and comprehends the discourse.Through a close examination of the results of the textual analysis and the empirical studies，it is found that the ways the three levels of coherence work in the textual arrangement and the reader's cognitive mechanisms are deeply interlinked.