Lexical bundles in classroom discourse
A corpus-based approach to tracking disciplinary variation and knowledge construction

Paul Doyle
English Language and Literature Academic Group / 
Centre for Research in Pedagogy and Practice
National Institute of Education
Nanyang Technological University
Singapore
paul.doyle@nie.edu.sg

Abstract
Corpus-based approaches to discourse analysis provide sophisticated analytical tools for investigating linguistic patterning beyond the clause level. Coupled with interpretations sensitive to the functional role of such patterning in texts, these approaches can facilitate deeper insights into differences between genres and registers, and, in the context of the discourse of primary and secondary classroom teaching, relate these understandings to broader pedagogic processes.  In this paper, I focus on recurrent word sequences, or lexical bundles (Biber et al. 1999), as markers of disciplinary variation in a corpus of primary and secondary teacher talk. Frequently occurring lexical bundles, such as “you know how to”, “I want you to” and “if you look at”, can be classified using functional categories such as epistemic stance expressions, modality and topic related discourse organising expressions (ibid). However, in order to account for variation in lexical bundle distribution across disciplines, there is a need for an interpretative framework that relates to a specific community of language users operating in a single genre (Hyland, 2008). Classroom talk is a hybrid discourse (Biber, Conrad and Cortes, 2004) that exhibits both the characteristic interpersonal features of spoken language and ‘literate’ features of written language from textbooks, and it is especially rich in lexical bundles. Using data from the Singapore Corpus of Research in Education, an ongoing educational research project utilising a corpus of classroom interactions, textbooks and students artefacts in key curriculum disciplines, I trace variations in pedagogic practice as evidenced in teacher talk from English medium lessons in English language, Mathematics, Science and Social Studies in Singapore classrooms. Frequent lexical bundles are classified using a framework adapted from Hyland’s (2008) taxonomy, and the distribution of the various categories is compared across the four school disciplines. The approach is evaluated in terms of its ability to relate linguistic variation to significant disciplinary differences, and to highlight processes of knowledge construction in the classroom.

1  Introduction
In this paper, I trace disciplinarity in teacher talk using the Singapore Corpus of Research in Education (Doyle & Hong, 2009; Hong, 2005), a corpus of some 600 classroom transcripts created from audio and video recordings of lessons from Singapore Primary and Secondary schools made between 2003 and 2005. The corpus comprises lessons conducted in English, Mandarin, Malay and Tamil but, for the purposes of this paper, I will focus purely on English medium instruction for the following subjects: English Language, Mathematics, Science and Social Studies, for which there are a total of 455 transcripts. 
Before examining this data closely, I will briefly discuss the concept of ‘disciplinarity’, and explain the method used to trace disciplinarity in the Singapore Corpus of Research Education (SCoRE). Then corpus-based methods for discourse analysis are briefly reviewed and the benefits such methods offer researchers interested in learning more about pedagogy from an empirical perspective are highlighted. Lastly, the concept of a lexical bundle (Biber et al, 1999) is discussed as the principle methodological framework for investigating disciplinarity in classroom discourse.

2  Background
This section provides the theoretical background to the study by looking in turn at the concept of disciplinarity, corpus-based methodology for discourse analysis, and the linguistic notion of a lexical bundle.
2.1  Disciplinarity
What is disciplinarity? A sociological view would be that it is the distinctive epistemological configurations of knowledge claims, bases for evidence and argument structures, and what is taken as a ‘fact’ within the discipline, which make up what we call ‘science’, ‘humanities’, mathematics’, and so on. Disciplinarity is critically concerned with questions of how differences in the structures of knowledge domains and curricula help shape educational experiences and outcomes.  It has been the focus of studies across a variety of disciplines using a range of approaches. 
From an applied linguistic perspective, disciplinarity has been partially aligned with the sociolinguistic concepts of register and genre, especially as those concepts have been developed by Michael Halliday and his followers (Halliday, 1994; Martin, 1990; Christie, 2000) within systemic functional linguistics. Recent collaborative work by followers of the sociologist Basil Bernstein and of Halliday has evolved a rich discussion of disciplinarity in the context of pedagogy and language (Christie & Macken-Horarik, 2008; Schleppegrell, 2008; Maton & Muller, 2007; Christie & Martin, 2007), with a particular focus on educational discourses. 
One key aspect of this, at least for systemic functional linguists and register/genre theorists, is the examination of classroom discourse (e.g. Christie, 2002; Schleppegrell, 2004) as a suitable site, amongst others such as curriculum documents and national tests, for the exploration of the language of the educational discourse of Mathematics. It is an assumption of this study that, to a significant extent, the way in which subject teachers ‘talk out’ their knowledge in the classroom can reveal differences in disciplinarity across the curriculum.
2.2 Corpus-based methods of discourse analysis
In recent years in applied linguistic research, the power and value of the corpus as an explanatory tool has grown exponentially, informing first work in lexicography (such as the COBUILD project led by Sinclair, 1987) grammar, and language description (Biber et al, 1999), but subsequently penetrating many different sub fields of the discipline, including discourse analysis (Baker, 2008; Stubbs, 2006). One of the claims that corpus linguists make is that their work is empirical: it takes a data-driven approach to the analysis of the language we speak and use, rather than the psycholinguistic appeal to ‘intuition’ and ‘native speaker’ inherent knowledge of language. When a corpus is compiled that is of sufficient size and diversity to be considered representative, and balanced in terms of the language or language genres it is attempting to investigate, we can be more confident that we are taking an empirical, scientific approach, not least because the studies we do will be replicable. Corpus-based studies of language reveal what is frequent and typical about language use in a way that is verifiable from the factual data: the words that people actually speak and write, rather than what they think they speak and write.
Thus, in this paper, the words spoken by teachers in the classroom are the basis of the investigation of what they do through language when they teach their subject disciplines. The Singapore Corpus of Research in Education (SCoRE) was designed to be representative of the Singapore context in which the data was collected. Schools and subject teachers were selected so as to create a balanced corpus of primary and secondary teaching. There are 455 transcripts of lessons, representing 121 teachers at Primary 5 and Secondary 3 level, teaching full units of work in four core curriculum subjects: English Language, Mathematics, Science and Social Studies.
2.3 Lexical bundles
The means by which disciplinarity is investigated in this study is through a comparative analysis of lexical bundles occurring in the four sub corpora of teaching subjects. Lexical bundles, also termed “multiword sequences” (Stubbs, 2007) or “clusters” (Scott, 2006; Mahlberg, 2007) or “recurrent multiword combinations” (Altenberg, 1998), are a feature of the phraseology of language. A lexical bundle is said to be a sequence of three, four, five or more contiguous words in the classroom talk that occurs above a threshold frequency. A detailed treatment of lexical bundles can be found in Biber et al (1999). Example 1 shows a typical occurrence of a lexical bundle from the SCoRE data:
Example 1	 I don’t know how1
This example illustrates two features that are typical of lexical bundles. Firstly, they are syntactically incomplete. Lexical bundles typically cross phrase or clause boundaries. In Example 1, the first clause “I don’t know” is followed by “how” which is the beginning of a second dependent clause (for example, “how to answer that”). 
The second feature of lexical bundles becomes apparent when we compare them with the similar category of fixed expressions, which includes idioms and other phrasal language constructions. True idioms are usually infrequent and are normally semantically opaque; that is, they carry metaphorical meaning such as, for example, “A bird in the hand is worth two in the bush”. Idioms are striking and memorable – but corpus-based studies (e.g. Moon, 1998) have shown they are quite rare. Lexical bundles, in contrast, are quite unremarkable semantically speaking, but they are much more frequent, especially in spoken discourse. 
In the SCoRE data, some 20 – 25% of the total words in our corpus are contained within lexical bundles comprising four words. Sinclair (2004) has claimed that as much as 80% of spoken text may be made up of phrasal language, and if this is the case then it is clearly important to examine their role in constructing teachers’ talk in classrooms.
2.4  Classifying lexical bundles
Lexical bundles can be classified in terms of their formal linguistic aspects and their functional role in texts. I will focus on the latter here, as I believe this has more efficacy for the exploration of disciplinarity, and fits well with the systemic functional linguistic approach to classroom discourse adopted by Christie (2002), Schleppegrell (2004) and others.
 Biber, Conrad & Cortes (2004) identify three main discourse functions for lexical bundles: stance expressions, discourse organizers and referential expressions. Stance expressions carry epistemic evaluations or attitudinal / modality meanings. Table 1 gives some examples of stance lexical bundles from the SCoRE data.

Epistemic: 	I don’t know whether we have time to complete the discussion.	
Desire:	I want you to elaborate on each point.	
Obligation (directive):	and you have to think what started the fire.	
Intention/prediction: 	Today, class, we are going to learn about formation of, er, Malaysia.	
Ability:	You have to be able to identify the different parts.	
Table 1  Categories of stance oriented lexical bundles in SCoRE (after Biber, Conrad & Cortes, 2004).

Discourse organisers indicate overall discourse structure and to signal the informational status of statements: topic introductions, topic elaborations/clarifications, and identification/focus. Table 2 shows some examples of lexical bundles from the SCoRE data with a discourse organising function.

Topic introduction: 	So, if you look at the main seed, you realise it’s not like a bean seed.	
Topic elaboration/clarification: 	What do you mean by do more with less?	
Identification/focus:	This is the one which is semi-permeable.	
Table 2  Categories of discourse organising lexical bundles in SCoRE (after Biber, Conrad & Cortes, 2004).

Referential expressions identify an entity or single out some particular attribute of an entity as especially important and include: imprecision indicators,  attribute specifiers, and expressions relating to time/place/text – deixis. Table 3 presents examples of lexical bundles from the SCoRE data which carry a referential function.

Imprecision:	This is probably some connection to the lungs or something like that lah	
Attribute specifiers
(a) quantity:
(b) tangible:
(c) intangible:	
How many of you are done with simple machines?
If I blow up the atom to the size of the stadium…
Okay, in the case of the African tulip seeds, what’s the method of dispersal?	
Time/place/text deixis:	you are applying a force at the same time 	
Table 3  Categories of referential lexical bundles in SCoRE (after Biber, Conrad & Cortes, 2004).

A fourth category found to be particularly prevalent in the classroom discourse was that of formulaic phrases with a politeness function. Table 4 gives some of the most frequent examples from the SCoRE data.

Politeness formulae:	good morning class good (morning)
thank you class thank (you)
thank you very much	
Table 4 Politeness formulae in lexical bundles in SCoRE data.

It should be noted here that the SCoRE data features many examples of Singapore English, as in the example in Table 3 for the referential category of ‘imprecision’ where the discourse particle “lah” comes at the end of the utterance. Although it is not a focus of this study, the presence of this English variety in some of the lexical bundles should be expected (for more detailed discussion of this, see Doyle, 2009 and for a concise description of the Singapore English variety, see Deterding, 2007).
2.5 Using lexical bundles to analyse discourse
In recent years, a number of scholars have used lexical bundles as a means of exploring linguistic variation in corpora (Hyland, 2008a; Csomay, 2007, 2005; Biber & Barbieri, 2007; Mauranen, 2006; Scott & Tribble, 2006; Simpson-Vlach, 2006; Biber, Conrad & Cortes, 2003) and in particular the language of the classroom (Csomay, 2007; Thompson, 2006; Biber, Conrad & Cortes, 2004; ) and student writing (Hyland, 2008b; Cortes, 2006, 2004).   
Biber, Conrad and Cortes (2004) studied the occurrence lexical bundles in university registers: tutorials and textbooks, and found some interesting similarities and differences. One of their key findings was that classroom talk (here referring to university tutorials) contains more lexical bundles than either lectures or textbooks alone, and that this can be explained by the fact that lexical bundles characteristic of these spoken and written pedagogical modes both occur in classroom talk. Lexical bundles found in spoken registers are typically centred on pronouns and clause fragments (a verb) – for example, you want me to, whereas those found in written registers tend to be centred on nouns – for example, the nature of the and as a result of. Biber, Conrad and Cortes (2004) found that classroom discourse contains both types of lexical bundle. They argue that classroom teaching displays similarities to textbook language, at least at the university level, by containing lexical bundles more typical of academic written registers, such as referential expressions (or something like that), as well as containing lexical bundles with discourse organising functions not found in textbooks or conversation, such as want to talk about.
Nesi and Basturkmen (2006) used the BASE corpus to look at the discourse signalling role of lexical bundles. They found broad similarities with Biber, Conrad and Cortes (2004) in terms of the top twenty lexical bundles occurring in lectures, and ample use of ‘topic introduction/focus’ lexical bundles.
Hyland (2008) has also looked at the role in academic discourse. His particular focus was on written academic registers and the extent to which lexical bundles varied by discipline, in a corpus containing research articles, PhD theses and MA/MSc dissertations from four disciplines: electrical engineering, microbiology, business studies and applied linguistics. He found “considerable differences” (Hyland, 2008a: 11) in the occurrence an frequency order of the top 50 four-word lexical bundles across the four disciplines: “over half the items in each (frequency) list do not occur at all in any other discipline and only 30% of the strings in each discipline are found in two other fields” (ibid: 12). In addition, he found only 5 of the four-word lexical bundles occurred in all four disciplines and only 14 in three disciplines (Hyland, 2008a: 12-13).
A key issue, then, is determining to what extent primary and secondary school academic spoken discourse shares these characteristics with tertiary level registers.

3  Methodology
To find the most frequent lexical bundles in the SCoRE data, the Wordsmith Tools software (Scott, 2006) was used to produce a word list index for all 455 transcripts. This index facilitated the use of the cluster tool in Wordsmith Tools.  
The minimum frequency for inclusion in a frequency list of lexical bundles was set at 10 occurrences. The method for determining whether a lexical bundle would be ‘delimited’ in any way was set to ‘sentence breaks’ for the purpose of this study. 
Frequency lists of 3, 4 and 5 word-long lexical bundles were created for each subject sub-corpus: English Language, Mathematics, Sciences. and Social Studies. These lists were then exported as Microsoft Excel format files, and that program’s statistical, graphical and list management tools were used to manipulate and then analyse the lexical bundles frequency lists. 
In addition to generating frequency lists, a lexical bundles analysis was carried out using the Wordsmith Tools keywords feature. A ‘keyword’ is defined  as a word that has a significantly higher frequency in a target corpus or text when compared to a reference corpus. Frequencies for the item in both corpora are compared and a ‘keyness value’ is calculated using a statistical procedure known as Dunning’s Log likelihood function (Dunning, 1993; Oakes, 1998:172). The significance of keyword comparisons according to Scott & Tribble (2006) is that the items revealed as key are generally those most typical of the target text: “what the text is really about, avoiding trivia and insignificant detail”. (Scott & Tribble, 2006: 56). 
In this case, the keyword comparison was conducted on the frequency lists for the lexical bundles, following Mauranen (2006: 279), producing a list of key lexical bundles for each subject. In each case, the reference corpus was the combined transcripts from the other three subjects. Thus, this analysis reveals what is distinctive, in terms of lexical bundles, about each subject.
Following Biber, Cortes and Conrad (2004) and Hyland (2008), it was decided to focus on the four-word lexical bundles. Others have argued for looking at longer sequences, especially in written texts (for example, Mahlberg, 2007), but it was felt that the interactional nature of classroom discourse would mitigate against success here. The longest lexical bundle in SCoRE, other than counting sequences, contains nine words: now this is what I want you to do. It has a frequency of 10 occurrences in just 7 transcripts.
3.1 Interpreting the frequencies
While the frequency lists of lexical bundles in the corpus are useful when comparing the data with other corpora, they still need to be interpreted carefully to check whether they have a single function across all subjects. An example will make this point clearer.
The analysis showed that one of the most frequent lexical bundles in the SCoRE data is the sequence one two three four , a counting sequence which occurred 350 times. Furthermore, this sequence occurred in 135 transcripts out of 455 (29.7%) and across all four subjects, which suggested that it has a general pedagogic function rather than a subject specific one. The discussion below shows how this lexical bundle was further analysed using the Concordance tool in Wordsmith Tools.
To explore this lexical bundle further, a concordance was generated (see Figure 3 in Appendix 2) which consists of a line for every occurrence of the lexical bundle in all the transcripts surrounded by a partial context. Clicking on one of these lines in the concordance display opens a window showing the full context, i.e. the transcript itself, allowing the function of that instance of the lexical bundle to be analysed. 
Two occurrences of the lexical bundle one two three four, one from a Mathematics lesson (Figure 1) and one from an English Language lesson (Figure 2) are shown below.

Trn0517 spk	I want two pieces out of five, how many pieces must I take away?
Trn0518 spk2	[…] Two! three!
Trn0519 spk8	Two!
Trn0520 spk7	Okay! Out of five pieces of cake, I want two. I give away three. Alright! Right. So three take out! Okay. Out of eight pieces, I only want three. How many do I take away?
Trn0521 spk2	[…] Five!
Trn0522 spk7	One, two, three, four, five. So is three eighth bigger or two fifth bigger?
Trn0523 spk8	Two fifth.
Trn0524 spk9	Two fifth bigger.	
Figure 1: Lexical bundles in a Maths lesson (SCoRE transcript: score_maths_012).

Trn0086 spk12	Now there are twenty seven, there are twenty seven of you. I'm going to divide the group in to three and I'm going to give you a number so that number one will go first, number two and so on okay.
Trn0087 spk15	Sit with Rafie.
Trn0088 spk12	Cannot. Why you in love with him?
Trn0089 spk15	Kurubu.
Trn0090 spk16	Kurubu.
Trn0091 spk12	No Kurubu, no nothing. I divide you, Kurubu.
Trn0092 spk14	Kurubu.
Trn0093 spk12	One, two, three, four, five, six, seven, eight, nine. Remember your numbers. You are team "A", Abu ah Abu.	
Figure 2 Lexical bundle in an English Language lesson (SCoRE transcript: score_eng_018).

What these two examples demonstrate is that a lexical bundle can serve different purposes in different contexts. In the maths lesson, it is used as part of the explanation of the subtraction procedure in a discussion of fractions; in the English language lesson, is part of the organisational language for setting up groups. Similar variation can be found in Science and Social Studies lessons.

4  Findings
A search for four-word lexical bundles in SCoRE located 119,418 instances with a frequency of 10 or higher, and 5,477 different four-word lexical bundles each with a frequency of 10 or higher, in 2.28 millions words.  This means that 2,396 different lexical bundles occurred per million words. In comparison, Nesi and Basturkmen (2006), examining lectures from the BASE corpus and the Michigan Corpus of Spoken Academic English (MICASE), found just 996 different four-word lexical bundles per million words. This difference is evidence for a greater degree of formulaic language used in classroom interactions between teacher and students in Singapore as compared to monologic lectures (over 2.4 times more) in a British university context. 
One reason for more formulaic language is likely to be that classroom discourse comprises, at least in part, conventional ways of doing things that teachers repeat across lessons and subjects. The data in SCoRE bears this out. Looked at as a percentage of the total words in the SCoRE corpus, the total words found in four-words lexical bundles comprised almost 21% of the corpus. If three-word lexical bundles were also taken into account, the figure would be greater still. Most studies show that three-word lexical bundles are about five times more frequent than four-word lexical bundles in corpora. In SCoRE, there were 451,384 three-word lexical bundles found with a frequency greater than 10, and 14,873 different three-word lexical bundles: these three-word lexical bundles make up nearly 60% of the whole corpus in terms of words2. 
How does this compare with other corpora of spoken academic discourse? Looking at lectures in BASE, Thompson (2006) noted the prevalence of what he termed discourse organising four-word ‘clusters’ (i.e. lexical bundles) in that corpus. Table 5 shows the ten most frequent four-word lexical bundles from the British Academic Spoken English (BASE) corpus (Thompson, 2006) and the ten most frequent lexical bundles in the teachers’ talk in SCoRE. 

Rank	BASE	SCoRE	
1	we are going to	I want you to	
2	I am going to	how many of you	
3	you are going to	you are going to	
4	I do not know	if you want to	
5	you have got a	we are going to	
6	the end of the	what do you think	
7	is going to be	I don’t want to	
8	at the end of	you look at the	
9	it’s going to be	one two three four	
10	it is going to	what do you mean	
Table 5  Ten most frequent four-word lexical bundles in BASE and SCoRE.

Only two lexical bundles, we are going to and you are going to are common to both sets, and there are some differences of interest. The school classroom discourse represented in SCoRE appears to have a more interactional emphasis rather than an organisational one. There is evidence of question forms (how many of you, what do you think, and what do you mean) as well as modal stance (if you want to, I want you to and I don’t want to) related to getting people to do things. This is consistent with a view of a lecture as essentially monologic speech genre and  classroom lesson as predominantly (but not exclusively) interactional and dialogic3.
If we look at the SCoRE data from a disciplinary perspective, differences become apparent within this interactional discourse. The percentage of words found in lexical bundles compared to the total number of words in the Maths sub-corpus is almost 25% (24.96), whereas the other subjects have lesser percentages: English language being just under 21% (20.75), with Science and Social Studies both around 14% (14.57 and 14.14 respectively). One implication to draw from this is that Mathematics teaching displays a greater reliance on formulaic phrases than the other subjects.
Moreover, if we compare the ten most frequent four-word lexical bundles across the three subject areas in SCoRE, we find there is little difference among the lists. Table 6 shows these lists for Maths, EL and Science. What Table 6 reveals is that, in terms of the most frequent lexical bundles found, the three curriculum subjects have more in common with each other than with the lectures. This is, in part, a confirmation that we are looking at different genres, and of the differences between monologic and dialogic academic spoken discourses.

Rank	English Language	Maths	Science	
1	I want you to	I want you to	I want you to	
2	if you want to	how many of you	you look at the	
3	you are going to	you know how to	what do you think	
4	how many of you	you are supposed to	we are going to	
5	what do you think	we are going to	you are going to	
6	do you want to	one two three four	if you look at 	
7	we are going to	know how to do	I don’t want to	
8	I don’t want to	what do you mean	how many of you	
9	you don’t have to	if you want to	one two three four	
10	don’t know how to	can you tell me	if you want to	
Table 6  Ten most frequent four-word lexical bundles in three subjects in SCoRE.

However, if we compare those lexical bundles that occur in at least 20% of all the transcripts within each subject sub corpus, we find again interesting differences (the reason for using a cut-off figure of 20% of all texts is to eliminate the idiosyncratic use of phrases by one or two teachers). Appendix 1 gives a list of these high frequency and widely distributed lexical bundles by each subject. It also shows which lexical bundles are common to all four subjects, which lexical bundles are unique to one subject, and which subjects ‘avoid’ lexical bundles that the other three subjects all share.
As noted above, Mathematics appears to depend more on lexical bundles than the other subjects. Not only this, it has the greatest number of ‘unique’ lexical bundles. When we examine the lexical bundles generated by the keyword comparison procedure in Wordsmith Tools, this becomes more apparent, as will be described in the next section.

4.1  Distribution of categories across the four school disciplines
Analysing the data shown in Appendix 1 reveals some interesting aspects subject-specific classroom discourse. Subjects share many common ‘pedagogically-oriented’ bundles (e.g. how many of you) related to question and answer routines (IRFs), basic classroom directives and procedures (e.g. go back to your) and the dominant role of the teacher (e.g. I want you to). However, subjects also differ in which bundles are most used and vary in their lexical bundle ‘profiles’:
Maths teachers seem to use lexical bundles that frame metacognitive knowledge of procedures (e.g. how do you get, how do you know) significantly more than Science, English Language and Social Studies teachers.
Science teachers appear to use lexical bundles related to ‘events’ in class, around which they can form a narrative: now I want you, and which are source of visual evidence: (e.g.  can you see that,  now look at the)
English teachers frequently ask for opinions about third party motivations: (e.g. do you think they).
Thus, I would argue, there is evidence here for variations in discipline specific pedagogic practices in core curriculum subjects. While the differences are not as striking as Hyland (2008) found in written academic registers, perhaps partly obscured by the generic aspects of classroom practices such as regulatory talk which are common to all subjects, it is possible to link the differences found to disciplinary orientations.

4.2 Key lexical bundles
Examining the lexical bundles produced by the keyword comparison procedure reveals clearer evidence of disciplinary variation. The top 10 ‘key’ lexical bundles in English Language, Mathematics, Sciences and Social Studies transcripts are shown in Table 3. The analysis produces a somewhat skewed result: for Mathematics, there are 118 key lexical bundles and for English Language, there are 88, but for Science and Social Studies there are only 9 and 11 key lexical bundles respectively. This is partly explained by the smaller size of the Science and Social Studies sub corpora, but the figures are also a clear conformation of the earlier finding that Mathematics has a much higher dependence  on lexical bundles than the other subjects. 

English Language	Mathematics	Science	Social Studies	
sit on the floor	is that clear to	side of the heart	and so on and	
what did he do	that clear to you	zero point six metre	so you find that	
what's the meaning of	three hundred and sixty	the shape of the	on and so forth	
you want to write	hundred and eighty minus	then you tell me	trying to tell you	
in front of the	is the same as	the red blood cells	you do at home	
you can talk about	how do you get	thirty five point five	is the purpose of	
to come up with	how to find the	so you can see	so on and so	
you want to be	is it clear to	can you see that	if you look at	
look at the picture	it clear to you	take a look at	what is the purpose	
know how to spell	one hundred and eighty		and things like that	
do you think he	the ratio of the		a lot of people	
want you to read	I want to find			
the two of you	what do you get			
can anyone tell me	they are the same			
come up with the	want to find the			
Table 7  Fifteen most frequent key lexical bundles by school subject in SCoRE.

What the keyword comparison in Table 3 clearly shows are the lexical bundles most characteristic of each subject. An inspection of the full list4 shows that Mathematics has a number of items centred on the word “clear” (is that clear to, that clear to you, is it clear to, it clear to you) which are part of longer bundles (is that clear to you, is it clear to you) and which express a focus on checking understanding. The other subjects have no equivalent common lexical bundles, which suggest that this is a priority with Maths teachers. Similarly, Science has so you can see, can you see the, take a look at which all suggest the use of demonstration or experience as a means of  building learning. English, on the other hand, has a large number of lexical bundles that contain ‘think’ – do you think he, you think they are, do you think they – which are clearly related to third persons (i.e. characters in narratives) and which elicit students’ opinion. In fact the lexical bundle what do you think has a negative keyness value for Mathematics. That is, it is found statistically less frequently in Mathematics classroom talk than it is in the other subjects.

6  Conclusion
What the analyses above show is that, using the corpus-based approach we can identify meaningful variation among lexical bundles across subject disciplines. Furthermore, there is some evidence that these variation relate to different strategies for knowledge building in the classroom, although such a claim needs to be supported by additional, qualitative analyses of these lexical bundles in the context of their transcripts.
In classrooms, students are not only expected to listen to teacher talk, they must also demonstrate participation in the discourse by responding appropriately when called upon by a teacher to answer a question, and furthermore they are expected to act. Students are frequently directed by teachers to act: to open their books at a certain page, to move and form groups, to come to the front of the class, and so on. However, the extent to which they do these things, and the role of these events in knowledge construction in the classroom varies across the subject disciplines, as shown by the varying frequency and types of lexical bundles that characterise the different subject classroom discourses.  

Notes
1.  In this paper, lexical bundles are shown by underlining.
2.  It should be noted that many four-word lexical bundles subsume three-word lexical bundles, so the percentage figures for three-word and four-word lexical bundles cannot simply be added together here.
3.  I use ‘dialogic’ here in a purely neutral sense to contrast with monologic discourse and not as an echo of Alexander’s (2006)  notion of dialogic classroom teaching.
4.  The full list is not reproduced here for reasons of space but is available from the author on request.

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Appendix 1  Concordance display, Wordsmith Tools.

Figure 3  Concordance of the lexical bundle one two three four

Appendix 2
High Frequency Lexical Bundles in SCoRE: text coverage > 20%  in each Subject
English Language	Mathematics	Science	Social Studies	
are going to do				
are you going to	are you going to			
			a lot of people	
			are some of the	
at the end of				
		at the same time		
	can you see that			
	can you see the	can you see the		
	can you tell me	can you tell me	can you tell me	
		don't know how to		
do you know what	do you know what			
	do you mean by			
do you think the			do you think the	
do you think they			do you think they	
do you want to	do you want to		do you want to	
don't know how to	don't know how to			
	don't want you to			
go back to your	go back to your			
going to give you			going to give you	
	how do you get			
	how do you know			
how many of you	how many of you	how many of you	how many of you	
	how to find the			
	I am going to		I am going to	
I ask you to	I ask you to			
I don't know how				
I don't want to	I don't want to	I don't want to	I don't want to	
	I don't want you			
			I just want to	
			I need you to	
I want to see	I want to see	I want to see	I want to see	
I want you to	I want you to	I want you to	I want you to	
I will give you	I will give you		I will give you	
		if you look at	if you look at	
if you want to	if you want to	if you want to	if you want to	
	is the same as			
	know how to do	know how to do		
let's look at the				
			let's take a look	
many of you have				
	now I want you	now I want you		
	okay this is the		okay so this is	
one two three four	one two three four	one two three four	one two three four	
	should be able to			
so that you can				
	so this is the	so this is the	so this is the	
so what do you	so what do you			
	so what is the			
so you have to	so you have to			
		take a look at	take a look at	
	tell me what is	tell me what is		
	thank you very much			
the end of the				
the rest of the		the rest of the		
the rest of you	the rest of you	the rest of you	the rest of you	
	they are the same			
those of you who	those of you who			
to look at the		to look at the		
two three four five	two three four five	two three four five	two three four five	
	want to find the			
want you to do	want you to do	want you to do		
we are going to	we are going to	we are going to	we are going to	
	what do you do			
	what do you get			
what do you mean	what do you mean	what do you mean	what do you mean	
what do you think	what do you think	what do you think	what do you think	
	what is the answer			
what I want you				
why do you think		why do you think	why do you think	
you are going to	you are going to	you are going to	you are going to	
	you are supposed to		you are supposed to	
	you can do it			
you don't have to	you don't have to	you don't have to	you don't have to	
you have to do	you have to do			
	you know how to	you know how to		
you look at the	you look at the	you look at the	you look at the	
	you look at this			
		you look at your		
	you tell me what			
		you to look at		
	you want me to			
	you want to find			
you want to go				
Total:                 41	57	31	32	
Unique:                  8	21	4	5	
Avoided:                2	1	2		

Lexical bundles common to all subjects, and thus not indicative of disciplinarity, are shown in the shaded rows. Lexical bundles ‘unique’ to a subject are shown in bold. 
For lexical bundles that are found in all but one subject, the empty subject slot is shaded. For example, “can you tell me” is found in Mathematics, Science and Social Studies, but ‘avoided’ in English Language.