8.1.2　Analytical framework for coherence construction in multimodal discourses

The genre analysis of the English learning advertisements suggests that the traditional approaches to coherence which are based on purely linguistic texts cannot accommodate the complexity in this special multimodal genre.Therefore，a new，multidimensioned framework for analyzing discourse coherence is needed in this book.

However，this is by no means an easy task.The existing studies on coherence usually limit their scope in the linguistic texts and do not consider the multimodal discourses.It is understandable since analysis of multimodal discourses must resort to interdisciplinary expertise and tools because more than one semiotic mode are involved.As Bateman（2008：7）says，“multimodal documents are a carrier of meaning that draws on visual，spatial and verbal presentational modes in combination and co-operation.This kind of meaning is locatable neither within traditional linguistic views of text nor within traditional views of the image”.Therefore，“analytic methods for handling this orchestration are few and far between”（Bateman，2008：1）.It is not unexpected that the analytical tools for coherence construction in the complexity of orchestration between various semiotic modes are even less.

To address this problem，this book takes a social semiotic view towards the combination of visual and verbal semiotic elements.That is，their commonalities in the semiotic capability of signification are sought after whereas their differences in the ways of expressing meaning are put aside.The reason is that，as discrete signs，whether verbal，pictorial or graphical，they all function to the whole structured discourse as bricks to a whole building.It is their role and function in the weaving of texture that are emphasized in this book rather than their characteristics in making different kinds of meaning.At the same time，the special features of multimodal discourses are also taken into consideration to make appropriate modifications to the coherence theories developed from purely linguistic texts.

This book puts forward a comprehensive framework to analyze the construction of coherence in complex multimodal discourses.The framework comprises three levels：global coherence，local coherence and surface cohesion.

Global coherence refers to the relevance with the discourse topical structure which exerts the macro-control over the whole discourse.That is，through the network of topics at various levels，it commands what verbal and visual meanings should be arranged into the different slots in the whole topical structure.

Local coherence refers to the information linking between visual and verbal elements in smaller discourse sections.It ensures that the adjacent elements are semantically connected.This inter-element relationship is the focus of the existing research on visualverbal relations in the field of multimodal discourse analysis.

Surface cohesion refers to the typographical features in the layout which serve to signal discourse structure and relative importance of elements.It equals somewhat to the cohesive devices in the purely verbal texts in function.That is，it is the formal signal or cue of the coherence relations in the discourses.However，in multimodal discourses the cohesive devices take on a totally different look—the typographical resources that help clarify the structure of the whole discourse and the information relations among various semiotic elements，including verbal，pictorial and graphical.

The relationships between the three levels are also discussed.Specifically，global coherence enjoys priority over local coherence and surface cohesion.Compared to global coherence and local coherence which operate at the content level of discourse，surface cohesion in layout functions at the expression level;therefore，its status is not as important as the other two.However，its effects on the multimodal discourses are by no means to be ignored.The evidence can be found in the fact that the poor use of the cohesive devices in the layout will cause a range of negative consequences，such as loss of interest，difficulty in reading and confusion in processing.（Bateman，2009）.

Having noticed that the current situation of multimodality research is“promissory”and“progress fragmented”，Bateman（2009）proposes，

By combining distinct layers of analysis within a single，coherent and evaluable model such as that proposed in the GeM framework，we should be in a better position for this and for achieving an understanding of how multimodal artefacts function.（Bateman，2009：64）

The three-level framework of coherence construction proposed in this book can be regarded as another research effort，apart from his GeM framework.The three layers of semiotic configuration give us a concrete place to start and enable us to achieve clear，systematic，empirically sound and effective analysis results.