3.2.2 Stratification and realization
Language is a complex semiotic system,composing various levels or strata(Halliday & Matthiessen,2004:24).In SFL,language is modeled in four strata of abstraction:phonology and phonetics,lexicogrammar,discourse semantics and context.
Figure 3.3 Stratification(from Halliday & Matthiessen,2004:25)
Figure 3.3 shows that there are two planes of stratification:expression and content.Phonology and phonetics are on the expression plane while lexicogrammar and discourse semantics are on the content plane.The content plane allows the meaning potential of a language to expand(Halliday,1984;Halliday & Matthiessen,1999;Halliday & Matthiessen,2004).Both the content plane and the expression plane are influenced by the context.The relationship among the strata,i.e.,the process of linking one level of organization with another,is called realisation(Halliday & Matthiessen,2004:26).Realisation is a kind of re-coding,like the mapping of hardware through software to the images and words we see on the screen of our computers.The concept of realisation embodies the meanings of“symbolising”,“encoding”,“expressing”,“manifesting”and so on(Martin & Rose,2003).Thus,choices in the systems at the discourse semantic level are realised by choices in lexicogrammar which are further realised by the choices in phonological expressions.
The current research aims to analyze the roles of CMs in the interaction between the authors and the readers in the EAPs of various disciplines and by both AEs and ANEs.This means that the research of CMs has to connect with what goes on outside the language,i.e.,the influence of disciplines and the authors’backgrounds.At the same time,CMs on the content plane can construe authorial stance and at the same time they are divided into two types which are realized by numerous lexicogrammatical conjunctive forms.Figure 3.4 presents the general condition of statification of the dissertation.
Seen from Figure 3.4,both of CMs and authorial stance are on the content plane.CMs can be considered as one type of lexicogrammatical realizations which could construe authorial stance.At the same time,the authorial stance on the semantic plane and the CMs on the lexicogrammatical plane are influenced by context,i.e,the nature of various disciplines such as the research methodologies,the author’s roles,the knowledge types and different linguistic-cultural backgrounds of the authors such as writing conventions,writer-reader responsible prose,etc.which can greatly influence the use of CMs in the EAPs.
Figure 3.4 Stratification of the current dissertation