Chapter 1 Introduction

1.1 Research Background

In any situation in which we write or speak，the linguistic message conveys a substantial number of propositions，which are the fundamental bearers of truth and falsity.However，making assertions（which are either true or false）is not the only thing we do with language.The linguistic message also conveys our relation to the propositional content，both personal and social，as well as our relation to our audience，either implicit or explicit.In communication，we often express various attitudes toward propositions，and these propositional attitudes are what we refer to broadly as the writer/speaker’s evaluation.

Over the last several years，linguists have become increasingly interested in the linguistic mechanism used by speakers and writers to convey their personal attitude.Such investigations have been carried out under several different rubrics，including‘evaluation’（Hunston 1994；Thompson&Hunston 2000），‘intensity’（Labov 1984），‘affect’（Ochs 1989），‘evidentiality’（Chafe 1986），‘hedging’（Holmes 1988；Hyland 1998b；Lakoff 1972），‘metadiscourse’（Hyland 2005a），and‘stance’（Barton 1993；Beach&Anson 1992；Biber&Finegan 1988；Biber，Johansson，Leech，Conrad&Finegan 1999，Chapter 12；Conrad&Biber 2000；Precht 2000）.These investigations have been conducted with a variety of complementary methodologies，ranging from detailed descriptions of a single text sample to empirical analyses of general patterns in large computer-based corpora.

The personal response to or relationship with the propositional content has been discussed from a number of perspectives.Among all the research activities，investigations of attitudinal expressions in academic research texts have been especially popular.The upsurge of interest in this area is not accidental.The role of human judgment in data interpretation has already been widely accepted in the philosophy of science（e.g.Faust 1984；Kuhn 1970；Kuorany 1987；Van Frasen 1980），and it is believed that the way to present findings is no less important than the findings themselves（e.g.Hyland 2005a）.

While scientific discourse has traditionally been considered as objective，impersonal and matter-of-fact，more recent studies have attempted to analyze the range of forms used to show the writer’s stance towards either the content or the reader（e.g.Hyland 1998b，1998c）.Such studies have been motivated by the awareness that academic writing is not purely objective.With the confirmation of the importance of evaluation，the value-laden devices employed in research articles（RAs）have been a much researched area in the literature.

While previous studies have contributed significantly to our understanding of the interpersonal dimension of academic language，they have limitations in several aspects.First，most of the earliest work has been done on the basis of a collection of limited academic texts.Although the examples selected from the corpus are authentic and reflect the actual language use in the world of science，those studies are not strictly frequency-based and are unlikely to make distinctions between what is typical（and thus is particularly worth of studying）and what is not.

Second，most previous studies in this area have paid disproportionate amount of attention to single words（e.g.personal pronouns，reporting verbs and modal verbs）and a limited set of prepositional phrases such as in general.The rarity of large computerized academic corpora leads to a relatively limited knowledge of how clause-level expressions as composite wholes convey personal opinions.How such devices are used evaluatively has yet to be systematically explored.

Third，while much has been done on evaluation in English and Chinese academic texts，there has been little work explicitly comparing the devices employed by the two languages in science writing，and few attempts have been made to establish equivalence between English and Chinese evaluative lexical combinations.

This book attempts to address these gaps by providing a reasonably comprehensive description of evaluative devices at the clausal level in English academic texts and by identifying Chinese equivalents of such English expressions.The central focus of this book is on textual sentence stems（TSSs）which can be roughly defined as semi-fixed sentential sequences that occur frequently in an academic corpus and perform the interpersonal and textual function.Each TSS is realized by a number of actually attested lexical sequences（LSs）which are closely associated both formally and semantically.

TSSs refer to a special category of lexicalized sentence stems（LSSs）developed by Pawley&Syder（1983）.Different from Pawley&Syder’s theory-driven approach to phraseology，however，we shall investigate this phenomenon by following the tradition of corpus linguistics from the Firthian（Firth 1957b）notion of collocation to Sinclair’s（1991）idiom principle.While the pioneering empirical study of actual language use must be attributed to the two leading figures，some influential Sinclairian ways of describing the English language should also be made explicit，such as Hunston&Francis’s（2000）approach to use large amounts of corpus data to make discoveries about lexical items and the specific phraseological and grammatical patterns in which they regularly occur.

The purpose of establishing cross-linguistic equivalence invariably requires a discussion about the corpus-driven study of translation equivalence.Consistent with Sinclair et al.’s（1996a）notion of contextual equivalence and Tognini-Bonelli’s（2001，2002）proposal of procedural steps in the identification of translation equivalence，the step-by-step methodology will be grounded on formal，semantic and functional features.In view of this，three corpora will be principally used—one English-Chinese parallel corpus and two comparable corpora—and they will provide evidence for the arguments throughout.