A Study On The Grammaticalization Of English Topic Change Markers

As a common type of discourse marker(hereafter,DM),topic change markers(hereafter,TCMs)play a vital part in discourse cohesion and smooth communication.So far,studies on English TCMs have mainly focused on analyzing the pragmatic functions of individual case,by the way,from synchronic perspective.However,few studies paid attention to the detailed and systematic description on the historical changes of English TCMs in terms of syntactic and semantic features.This study intends to describe and interpret the historical development of English TCMs(by the way,incidentally and parenthetically)from diachronic perspective,combining the theories of DMs and grammaticalization.Based on the theory of grammaticalization and the data from 14 th century to the present collected from OED,COHA and EEBO,this study focuses on the historical development of by the way,incidentally and parenthetically and explores the mechanisms behind their historical changes.This thesis mainly answers three research questions below:(1)What are the historical paths of English TCMs(by the way,incidentally and parenthetically)?(2)What are the mechanisms of grammaticalization behind the historical changes of English TCMs?(3)What are the common characteristics in the grammaticalization of English TCMs?The three major findings of this study are listed as follows.First,by tracing the historical changes of these TCMs,this study discovers three types of distinctive developmental paths,which can be schematically illustrated below:i)by the way1: locative adverb(along the road)> by the way2: manner adverb(in passing)> by the way3: manner adverb(sentential: in passing)> by the way4: TCM ii)incidentally1: manner adverb(as a chance occurrence)> incidentally2: manner adverb(in passing)> incidentally3: TCM iii)parenthetically1: manner adverb(in a parenthetical manner)> parenthetically2: manner adverb(in passing)>parenthetically3: TCM.Second,regarding to the mechanisms that lead to the grammaticalization of TCMs by the way,incidentally and parenthetically,it is discussed that reanalysis and subjectification operate in the syntactic and semantic change respectively.Finally,in the process of grammaticalization,English TCMs exhibits the prominent characteristics shared by them,namely,unidirectionality,abstraction and coexistence.This study clarifies the historical paths of English TCMs and then reveals the mechanisms behind their historical changes within the framework of grammaticalization.It is not only a kind of extension and depth of the study of DMs,but also a supplement of the combination of grammaticalization and English TCMs.In addition,it provides references for English learners to accurately master English TCMs and the compilation of English dictionaries.