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Syntactic differences in oral and written scientific discourse: the role of information structure

Shirley Carter-Thomas et Elizabeth Rowley-Jolivet
p. 19-37


Nous examinerons dans cet article certaines différences syntaxiques qui se profilent à partir d’une comparaison entre une série de communications scientifiques orales faites par des chercheurs scientifiques anglophones lors d’un congrès de physique et les articles de recherche correspondant à ces communications, publiés dans les Actes du même congrès. Notre objectif n’est pas seulement de fournir un inventaire de ces différences mais également d’en proposer quelques explications. À notre avis, une analyse des différences syntaxiques relevées dans ces deux genres de discours scientifiques peut bénéficier d’une réflexion sur la notion linguistique de structuration informationnelle. Une telle approche permet en effet de cerner de plus près l’influence du contexte énonciatif sur les formes syntaxiques employées. Nous examinerons en particulier l’utilisation de quatre structures syntaxiques : l’extra-position, les énoncés existentiels, les inversions et les pseudo-clivées

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  • 1 See Appendix 1 for details of the conference and a list of the presentations and articles in the co (...)

1Different types of scientific discourse make use of a variety of syntactic structures in differing proportions. We have chosen to examine some differences in syntactic structure that emerge from two distinct discursive situations: the paper delivered orally at an international physics conference and the corresponding article as published in the conference proceedings.1

  • 2 There is some interesting work on university lectures, but this is didactic discourse and therefore (...)

2The motivation for this study is twofold. First, while there exists a considerable body of work on written scientific discourse, particularly the research article, we know much less about the syntactic features of the oral equivalent of the research article, namely the conference presentation.2 It is important to know more about the differences between how scientists write about their work and how they speak about it. Many of us in the GERAS community are involved in the design and teaching of academic presentation skills courses and the research article cannot be used as a model for giving a successful oral presentation —the two, we would contend, are different genres. A first step was therefore to evaluate certain syntactic differences between the two genres in quantitative terms. The issues centre on preferred structures, and a basic distinction is drawn between those common to the two genres and those which occur in only one of the two genres examined. Frequency of occurrence is therefore a key consideration.

3Our approach however is not restricted to the statistical level. The second objective for our study was to find explanations for the differences observed in the two genres and evaluate them in qualitative terms. What are the practical imperatives that lead to one structure being preferred to another? What is different about how the message is conveyed to a live audience in one case as opposed to the reader of the article in the other? Can the same type and quantity of information be transmitted? Why is certain information omitted or, on the contrary, highlighted? At the centre of such preoccupations is the linguistic concept of information structure. It is our contention that many of the syntactic differences between the oral and written conference papers can be usefully explained by looking at how information structure functions in these two very different communicative contexts.

1. Information structure

4Information structure deals with the way the information conveyed by the discourse in question is packaged into informational units within and between clauses by the enunciator (writer or speaker), in order to satisfy two communicative goals: i) making the information conveyed by the discourse easier for the reader/hearer to understand; ii) indicating what the enunciator considers to be the most important or salient items of information.

5Generally speaking the writer/speaker will place at the beginning of the clause what he is speaking about, the theme, which usually contains given (or recoverable) elements that the listener can easily identify. New elements of information concerning this theme will figure afterwards in the rheme. As a rule the clause will gradually gain in communicative importance with the most communicative dynamism, in the words of Firbas (1992), falling on elements which carry a substantial new information load in the rheme. In oral discourse in English this gain in communicative dynamism usually culminates in the focal nuclear stress being placed on an item in clause final position. The rise in information load also often corresponds to the actual size and complexity of clause items, with long complex elements tending to occur towards the end of the clause, thus easing the processing burden of the receiver, a phenomenon frequently referred to as ‘end-weight’.

  • 3 See Carter-Thomas (2000, Chap. 2) for a more detailed account of information structure and the inte (...)

6This type of organisation with given information first and new information second, reinforced by the principle of end-weight and final focal stress, is considered to be the unmarked option for organising the information. On the syntactic level unmarked information packaging arrangements are often rendered in English by an SVO structure, where the grammatical subject of an active verb provides the thematic anchorage, with the verb complex and object constituting the new or rhematic part of the clause.3 However this SVO order is not always sufficient or suitable to create a coherent text. In order to respect unmarked information structure the enunciator may be obliged to use a different syntactic arrangement. He may also choose to deliberately reverse the usual information packaging arrangements in order to give certain elements of information particular salience or focus. For these reasons, the enunciator needs to have at his disposal a battery of linguistic resources so as to indicate unambiguously, either through prosody or syntax, the information packaging arrangement desired.

7We have chosen to focus on the syntactic resources available for indicating information status and focus. At issue here are specialised syntactic structures, such as the passive, cleft constructions, extraposition, inversion and existential there, structures that specifically enable the enunciator to manipulate different clause constituents and thus explicitly denote a particular information packaging arrangement. Whilst these structures are theoretically available at all times, their deployment depends to a large degree on the choice of a particular enunciator, within a particular mode (oral or written) and communicative context.

2. Research design

8In order to investigate the precise impact of the communicative context and the mode on information packaging strategies and the consequent choice of syntactic structures employed, a corpus of strictly parallel texts was collected. This corpus comprises nine conference presentations given by native speakers of English at an international conference in physics, and the nine corresponding articles published in the proceedings of the conference. The oral presentations were recorded on video and then transcribed. The parameters held constant between the oral and written sub-sets are therefore as follows: the scientific research topic (identical for each presentation-article pair); the author (the speaker is in all cases one of the authors of the written paper); the audience targeted (other researchers in the same physics speciality); the occasion (the physics conference). The only variable parameter is the mode, oral or written.

9The first step in the analysis consisted in a quantitative comparison of the articles and presentations to establish the relative frequency of occurrence of the specialised syntactic structures in each sub-set. These comparative data are presented in the next section.

3. Quantitative data

Longman Grammar of Spoken and Written Englishet alLGSWE

10It should be noted that while the two sub-sets of articles and presentations are almost identical in length (19,475 and 19,502 words respectively), there is a much lower number of clauses in the proceedings articles (1,489 compared to 2,063 in the presentations), due to a lower verbal density: the verbal densities, expressed as the number of verbs per 1000 words are, respectively, 76.5°/oo (articles) and 103°/oo (presentations).

Table 1. Quantitative comparison of conference proceedings articles and oral presentations

Table 1. Quantitative comparison of conference proceedings articles and oral presentations

Mean percentage is given for the passive only; it is not indicated for the other specialised structures due to the small numbers involved

11It can be clearly seen from Table 1 that there are marked differences in the frequency of occurrence of the structures in the articles and oral presentations. Structures that are heavily used in one mode are absent, or used only to a minor degree, in the other mode, indicating that the strategies used to manipulate information structure are strongly mode-dependent.

12The passive will not be examined in detail in this paper, as it has been extensively studied elsewhere (Barber 1962; Hanania & Akhtar 1985; Banks 1993: 13-59; Tarone et al 1998), due to its high frequency of usage in scientific research articles. Note that the percentage of passives in the proceedings articles (32%) agrees with the figure of over 30% found by other studies of scientific journal articles, while the somewhat lower figure (25%) in LGSWE can be explained by the fact that the register ACAD includes not only scientific articles but also articles from other academic fields, where the passive is not used to the same extent. It should be stressed, however, that the passive plays an important role in information packaging, or more precisely in enabling the writer to match unmarked information structure with syntax (Carter-Thomas 1998: 76-78). By using a passive the writer can thematise and present as ‘Given’ what would normally have been a syntactic object (and thus part of the rheme) in an active clause. The use of a passive construction thus allows the writer to maintain thematic continuity between clauses, as an inanimate element already mentioned in a previous clause (either in the theme or rheme) can be thematised thanks to a passive in a subsequent clause.

13The oral presentations, in contrast, contain a relatively low percentage of passives (9%), even though the subject-matter is the same, indicative of the strong influence of the oral mode on the syntactically preferred structures. This difference is highly significant (p = 0.001). The low proportion of passives is correlated with a correspondingly high proportion of personal pronoun (animate) syntactic subjects used as themes in the oral presentations. A more detailed comparison of the use of the passive in conference proceedings and oral presentations can be found in Rowley-Jolivet (2001).

14Extraposition, another feature generally associated with scientific discourse, is, like the passive, typical only of the written mode and is rarely used in the oral presentations. Existential there, in contrast, shows exactly the opposite modal distribution, with four times the frequency in the oral presentations compared to the articles. The remaining two constructions that will be examined, namely inversions and wh-clefts, show the most marked mode-dependent distribution, with no occurrences in the articles, but an appreciable number in the presentations. Our figures here confirm both the data in LGSWE, where inversion and wh-clefts are found to be characteristically more common in conversation than in written academic English, and those given by Weinert and Miller (1996) on the use of wh-clefts in speech. It-cleft constructions are negligible in the data analysed here, with only 2 occurrences (1 per 10,000 words) in each mode, and will therefore not be discussed further. This figure is considerably lower than the figure of 12 per 10,000 words in academic prose given by LGSWE but corroborates the data in Banks (1995: 5).

15A clear overall trend emerges when the data for the oral presentations are compared with those from LGSWE: whatever the structure considered, the conference presentations bear more resemblance to the features of conversation than to those of academic prose.

4. Qualitative analysis of specialised syntactic structures

4.1. Extraposition

  • 4 These figures confirm those of Banks (1995: 6-9) as far as the written corpus is concerned. Note, h (...)

16In extraposition, the theme position of the matrix clause is filled by an anticipatory ‘it’, which refers to a clausal item occurring in the postponed extraposed clause. In our corpora, extraposition is basically of two kinds: finite ‘that’ clauses account for 70% of occurrences and non-finite infinitive clauses for 30%.4

  • 5 Examples taken from the proceedings articles are referred to by the letter A plus the number of the (...)

(1) Based on these results, it may be possible to design a uniform BWO where the forward traveling volume harmonics can serve the role of a prebuncher. (A14)5

(2) It is well-known that this behaviour arises from the inability of the dipoles within in the materials to respond (A4)

17While, however, finite extraposition dominates in our two data sets, extraposition in general is considerably more frequent in our written corpus of articles than in the oral presentations (see Table 1).

18There are several possible explanations for the frequent recourse to extraposition in the proceedings articles. Firstly, from the point of view of information structure, extraposition allows the writer to distribute the information load more evenly over the sentence. The use of a non-extraposed structure, as below, would have resulted in a very heavy and complex theme:

(?) Based on these results, designing (to design) a uniform BWO where the forward travelling volume harmonics can serve the role of a prebuncher may be possible.

19Extraposition makes it possible for the enunciator to avoid such heavy themes and thus respect the principle of end-weight.

20Linked to this first point is the fact that a heavy, complex theme as in the non-extraposed version above (?) is very likely to contain elements of new information. By using extraposition the writer ensures their rhematisation. Communicative dynamism thus coincides with the object of the ‘that’ or ‘to’ clause placed in the rheme.

21Another explanation for the frequency of extraposition in the scientific article concerns the phenomenon of hedging. Extraposition can be used as a hedging tactic. It allows the writer to thematise his own comment on the value or validity of the information in the extraposed clause; his point of view is objectivised by being placed in a separate ‘it’ clause:

(3) It is clear from these experiments that … (A4)

(4) It is expected that technological innovation will lead to advances in… (A14)

22Extraposition is in fact called ‘Thematised Comment’ in systemic linguistics for this reason (Thompson 1996: 129-130). The scientist can thus make a subtle commentary without appearing overtly in his text.

23Given the relatively high frequency with which extraposition is used in the articles, and the extremely low frequency in the oral presentations, we decided to compare all the extrapositions in the articles with the passages in the oral papers where the same information is presented, in order to discover what sort of structures are used orally to transmit the same information.

24However, in two-fifths of the cases, no comparison can be made, because the information in the extraposed clause in the article is omitted in the oral presentations, either because it is part of the literature review, which is very short or sometimes totally absent in oral presentations:

(5) It has been reported that the number of spark gaps can be reduced somewhat by using a high-voltage transformer pulsed from a capacitor bank [2,3] (A3)

25or because it is part of the ‘Materials & Methods section in the article, which is much less detailed in oral presentations:

(6) It is important that the silver tracks are intimately bonded onto the ceramic surface and there are no air gaps (A4)

26Generally speaking, in the oral presentations the speaker only has a limited amount of time, and therefore aims to convey a fairly simplified version of his results, without going into the finer distinctions.

27When these omissions are accounted for, we are still left, however, with a considerable number of cases where extraposition is used in the article, but not in the oral presentation, to communicate the same information. In no case, in fact, is the extraposition in the article paralleled by extraposition in the oral presentations.

28An initial point that needs making is that one of the main motivations for using extraposition is to avoid employing heavily pre- or postmodified nouns as theme. This consideration does not apply in the presentations, where in half of the clauses the role of theme is filled by a pronoun —which by definition cannot be pre- or postmodified— and in other cases noun modification is much lighter, due to constraints on real-time processing for both the speaker and the audience.

29This is illustrated in the following examples, from the oral presentation and article respectively. The scientist is making approximately the same point in each case:

(7) ... you want to stress it as far as possible and that’s limited by the breakdown field (P4)

(8) ... it is advantageous to stress the blocks to the maximum electric field that can be safely tolerated without breakdown. (A4)

  • 6 See Thomas (1999) for the different types of thematic progression used in scientific writing.

30However, whereas in the article the writer makes use of extraposition, thus avoiding placing a complex clausal theme in sentence initial position, in the oral presentation the need for such a response or tactic is obviated. The themes of each of the two clauses in the oral presentation are brief (‘you’ and ‘that’) and the linear progression operated6 (‘that’ refers back to the rheme of the preceding clause) enables the speaker to provide the required explanations progressively to the audience.

31Another reason for the frequent use of extraposition in the article is its function as a hedging tactic. Likewise this does not apply in the presentations, where speakers tend to express their evaluation and comments far more openly.

Table 2



It is shown that

we’ve demonstrated

It seems that

we think that probably

It is possible to define

we can define

It seemed that

we’ve developed an opinion

It has been found that

we find in practice

It can be implied that

we know

It is believed that

we believe

It is shown that

we’ve shown

It is hoped that X

X was a thought

32As table 2 makes clear, there is a strong association between the use of the passive and the use of extraposition in the articles: indeed, 26 (i.e., half of the 54) occurrences of extraposition in the articles use a passive verb. In the oral presentations, in contrast, the hedging typical of the research article (avoidance of first person pronouns) does not apply, and researchers freely take responsibility for their own opinions.

33The fact that speakers can manage without extraposition for hedging raises the possibility that some of the cases of extraposition found in the articles and that are considered to be hedges, may be, in fact, simply stylistic conventions of the article genre. We find some support for this in the fact that these types of expression —it should be noted that, it has been shown that— called lexical bundles by LGSWE are very stable collocations that are found only in academic prose.

34A final minor reason for the absence of extraposition in the oral presentations is that —whereas extraposition is used to refer to the Figures in the articles— in the oral presentations, visuals are referred to either with deictics (here’s..., this is...) or, when a verb is used, it is in the active form (see table 3).

Table 3



it can be seen in fig. 3

the top trace here shows

it can be seen that

here’s a picture of

it has been found that

the top graph shows

35Two points stand out from this analysis of extraposition. Firstly generic conventions would seem to have a strong bearing on the information packaging strategies used. This is both the case concerning conventions of style, as displayed by the use of hedging tactics, and conventions of content, certain sections of the research article being practically absent in the oral presentations. Secondly, contextual constraints, and in particular the real-time processing of information in the presentations also impact on the information packaging strategies that are available to speakers.

4.2. Existential there

36The existential there structure is used four times more frequently in the oral presentations than in the proceedings articles (see Table 1). This result differs from that of LGSWE, which reports a similar frequency for written academic prose and for conversation, namely 50 and 60 occurrences per 20,000 words respectively (as against 13 and 51 per 20,000 words in the data analysed here). The low count observed in our proceedings articles may possibly be an artefact of the small data set, for, as Banks (1995: 9) points out, there is considerable inter-author variation in the use of the existential there construction in scientific research articles. Nevertheless, the marked difference observed in the data raises the question as to whether the structure plays the same role in the two modes.

37We will first examine those functions of existential there as an information packaging device which are common to both the written texts and to the oral presentations, before going on to investigate what additional functions it may fulfil in the oral presentations.

38In existential there constructions, the Theme and Given position in the clause is filled by the semantically empty there. Any new elements of information can then be placed in rhematic position, in accordance with the traditional Given-New division. The basic function of this structure is therefore not to predicate a property of a referent but to introduce a brand-new referent into the discourse. It is for this reason that Lambrecht prefers to call this structure ‘presentational’ rather than ‘existential’:

From the point of view of information-structure analysis, the label ‘existential’ is somewhat misleading. Mere assertion of the existence of some entity is a rather special kind of speech act which is of limited use in everyday communication (...) it is therefore preferable to interpret the function of such sentences as that of presenting or introducing a referent into the ‘place’ or ‘scene’ of the discourse and thereby of raising it into the addressee’s consciousness, rather than of asserting its mere existence. (Lambrecht 1994: 179)

An example of this presentational function from the oral data is the following:

(9) here are some of the factors that influence the behaviour of dielectric, there’s obviously chemical composition [...] and then there’s external factors like temperature and the applied electric field ...(P4)

39In the articles, considerations of information load and end-weight are also relevant. As mentioned in the previous section on extraposition, noun groups in the scientific research article are often heavily pre- or postmodified. Placing the noun group in rhematic position, thanks to the existential there construction, avoids overloading the clausal theme, thus respecting the principle of end-weight, as in the following example:

(10) There is essentially no difference in spectral content between sharpening the leading or trailing edge of the pulse. (A2)

40There is no obvious canonical counterpart to existential there clauses, but any reformulation of this structure would normally entail presenting certain elements of information as Given:

(*?) Essentially no difference in spectral content occurs between sharpening the leading or trailing edge of the pulse.

41While considerations of end-weight concern more particularly the articles, a second function of the existential there structure that is common to both articles and presentations is its role in ensuring a smooth information flow between clauses. The new information introduced in the rheme of one clause is frequently taken up as theme of the subsequent clause, thus creating a linear progression. Example (11) below is an instance of simple linear progression, and example (12) of split linear progression, in which only one part of the preceding rheme becomes the subsequent theme. This second type of progression, as Dubois (1987) points out, is common in scientific discourse due to the complexity of the noun groups.

(11) In addition to the resonant charging network there is a high impedance power supply at the switched voltage. This maintains the drain voltage at low repetition rates. (A9)

(12) Since the characteristic impedance is Zo = (L/C)½, there is a trade-off between high voltage capability and low impedance. If the oscillator impedance is too high it will be severely loaded by the antenna... (A2)

42A final function of existential there shared by the articles and the presentations is that of asserting or denying the existence of a physical phenomenon. As Lambrecht, in the previously quoted passage (ibid. 179) remarks, this discourse function is rarely called upon in everyday conversation. In science, in contrast, it is essential to the establishment of scientific facts and theories. Some examples from the data are:

(13) it tapers out slowly so that we know there cannot be a hard arc there (P2)

(14) the Curie point is the point where there is a physical phase change in the material (P4)

(15) ...the paraelectric phase in which there is no spontaneous dipole moment (A4)

In this function, the label of ‘existential’ structure is fully warranted.

43In addition to these three roles, existential there appears to have other specific uses in the oral presentations which could explain its greater frequency in this mode. The first of these is its role in enumeration. In the presentations, there is / are frequently serves to initiate, to continue, or to conclude an enumeration of various features. In this function, it is generally preceded by a sequencer such as then (‘and then there’s a balanced Blumlein’: P2), or followed by a quantifier or a numeral:

(16) there are essentially three types of operation you can get ... there’s a stable operation ... and there’s a third one (P11)

(17) there are several techniques that we use (P9)

(18) there are two other factors (P13)

44By organising the listing, it helps the audience to process sequential information. In a written text, the organisation of an enumeration can be expressed by punctuation (colons, semicolons, bullets, etc.) and by page layout.

45A second function of existential there in the oral presentations is that of discourse organiser. In this role, the scope of there would seem to be considerably wider than in an enumeration, in that it serves to open or to close a segment of discourse dealing with a given topic. When preceded by now, there serves to initiate a whole new topic. This is closely related to the function traditionally attributed to existential there of introducing a new element into the rheme, but its association with now seems to further underline its role as a discourse organiser at the beginning of a section or sequence:

(19) now there’s lots of different ferroelectric materials (P4)

(20) now there’s a lot of data to show (P13)

46In the same way, there is also used as a discourse organiser to close a topic, by summing it up. In this case, there is regularly preceded by so / so that and has an anaphoric role of pointing back to a previous segment in the discourse:

(21) so there are practical applications in that area. (P13)

47In the written article, in contrast, topic opening and closing can be expressed by page layout (segmentation into paragraphs, section headings, etc.).

48Finally, in some cases, existential there is used to refer to what is shown on the visual, and is preceded either by an invitation to the audience to look at the visual or by a locative adverbial:

(22) as you can see, there’s almost exact correspondence of the DC part and even of the RF part (P11)

49The greater frequency of existential there in the oral presentations appears therefore to be related to the specific communicative context of this genre: in order to facilitate information processing for the audience, the speaker needs to indicate clearly, by using segmentation devices, how the discourse is organised; he also needs to refer constantly to the visual channel. The existential there construction is one of the specialised syntactic structures which answer these information packaging needs.

4.3. Inversion

50In a language such as English in which the SV(O) sequence is the canonical (or unmarked) word order, the reversal of this sequence has traditionally been referred to by the name of inversion. This syntactic manipulation of the clause can be of two kinds:

  • Subject/Operator inversion (or partial inversion), as in “Only then did she realise that...”

  • Subject/Verb inversion (or full inversion), as in “Here comes the sun”.

51Both are triggered by some element other than the subject being placed in clause-initial position.

52Subject/Operator inversion will not be examined here, as only 3 occurrences were found in the data. The proceedings papers contain one occurrence of grammatically constrained S/O inversion after as used for comparison:

(23) In addition, the degree of non-linearity induced will be lessened, as will the amount of pulse sharpening. (A4)

In the oral presentations, there is one occurrence of the same structure:

(24) laser diodes have been driven as have X-ray diodes (P3)

and one occurrence of a dependent interrogative clause with S/O inversion:

(25) so at least you’re getting a qualitative picture and you can identify what are the mode competition effects and so forth (P11)

53Inversion of the verb and syntactic subject, in contrast, is a frequently used structure, with 61 occurrences in the oral presentations. There are however no occurrences whatever of S/V inversion in the articles. The fronted element in the oral presentations is, in all cases, a locative adverbial expression, and the verb is the copula BE (see Table 4). This agrees with studies of various registers of English (Quirk et al 1985; LGSWE) which have shown that S/V inversion with the locative adverbials here / there + BE in the simple present is common in conversation but rare in writing. The pre-subject positioning of the verb is syntactically constrained since the adverbial expression constitutes part of the predicate.

Table 4. Subject/Verb Inversion in oral presentations: Clause-initial elements

Fronted element


here (here’s / here are)


there (there’s / there are)


other locative adverbials

on this axis is...

out to the left is...

in the centre is...etc.


Oral: 61 occ. Articles: 0 occ.

54The role of this structure in information packaging is, like the existential there construction discussed in the previous section, presentational in nature. Its communicative function is not to predicate a property of the referent but to introduce a brand-new referent into the discourse. Once it has been introduced, the referent is cognitively accessible and can then be taken up as the theme of the subsequent clause, as in example 26.

(26) here’s a picture of one of the devices; this one has plastic insulation, it runs from 2 to 300 kV reliably (P2)

55The high frequency of this syntactic structure in scientific conference presentations appears to be motivated by three features of the communicative context. The first one concerns the concurrent presence of two channels of communication, the verbal and the visual. As can be seen from Table 4, in all the cases of inversion observed in the data, the introductory term has a deictic function, signalling either the projection of a new visual on the screen, or pointing to a particular place on the visual already displayed. In 80% of the inversions with here, for example, the deictic is the first word pronounced by the speaker as he places a new transparency on the OHP, as the following extracts from one presentation (P2) illustrate:

Extracts from presentation P2

Transparency #

Opening words


here’s a picture of one of the devices


here’s a photograph of the line output


here’s a – I’ll try to do this real quickly


here’s a picture of the EMBL source


here’s the output waveform from the EMBL


here again is received electric field signal

56The frequent use of this type of inversion would appear to be directly related to the discourse context of the conference presentation, in which the speaker has constantly to integrate information from the visual and the verbal channels. He has first to focus the audience’s attention on the transparency before proceeding to explain what they can see there. We would follow Enkvist (1991) here in calling this a text strategy, which in this case overrules the canonical SV(O) order. It is the requirements of the discourse which determine what the appropriate information packaging arrangements are and the consequent use of syntactic structure.

... the syntactic arrangement of the sentence is not independent but subservient to a text strategy. The discourse is the father of the text, not vice versa, and each sentence must serve its discourse and text by confirming [sic] to its general strategic principles and thus linking up, deictically and stylistically, with the discoursal situation (Enkvist 1991: 16)

57A second function of this type of inversion is that the initial adverbials serve the purpose of segmenting the text into sections and sub-sections. Each visual projected can be seen as constituting a section or text unit, with here-inversion signalling the onset of a fresh unit. In several cases, there are sub-units, or hyponomies, within the unit. These are frequently signalled by the fronting of a more specific locative adverbial, as in example 27. The speaker, after having signalled the start of a new unit with here’s when he first shows the visual, then goes on, when commenting on the same visual, to signal sub-units with other inversions (on the left..., on the right...):

(27) here’s a typical confrontation with the experimental and computer simulation data, on the left are the [experimental] measurements of the DC and RF current for each of the cavities [...] and on the right are the corresponding curves one gets from simulations (P11)

58This allows the speaker to break up the complex visual information on the transparency into more digestible chunks for the audience.

59The third feature of the communicative context which motivates speakers’ recourse to inversion concerns the principle of end-weight. In all the cases where inversion is used, the noun group is much weightier than the initial adverbial element, and contains the new information:

(28) Here is two measurements of power density as a function of angle away from the central line of the horn antenna (P14)

60Inversion allows the speaker to place the heavy elements towards the end of the clause, following the principle of end-weight, and thus to ease the mental processing effort for the listener. This structure thereby contributes to creating an information flow that is adapted to the constraints of real-time speech.

61It is clear that inversion, in scientific conference presentations, is a pragmatically motivated structure, which answers specific discoursal requirements. Note moreover that in several cases (cf. example 28), here’s / there’s functions as a deictic block, with no agreement in number between the subject and copula. Indeed, the term ‘inversion’ itself –implying that the normal word order has been violated– seems to be a misnomer, in that it is the non-inverted word order which would appear ‘abnormal’ in this context. The inverted structure cannot therefore be considered as simply a variant on the canonical one.

(29) Here’s a typical confrontation with the experimental and computer simulation data

(?*) a typical confrontation with the experimental and computer simulation data is here

(*) Here a typical confrontation with the experimental and computer simulation data is

Indeed, in the above example, only the inverted structure would seem feasible.

4.4. Pseudo-clefts

62There are practically no occurrences of IT-clefts in our two data sets, but there are, however, a certain number of pseudo-clefts, all in the oral presentations (see Table 1). Pseudo-clefts can be of 2 types (Weinert & Miller 1996, LGSWE 1999): ordinary WH clefts (WH) and reverse WH clefts (RWH).

Ordinary WH-clefts (WH) have the following form:

WH-P’ is X

(30) What we did was...

63In reverse WH-clefts (RWH), on the other hand, the clefted constituent occurs in sentence initial position:

X is WH-P’

(31) it’s really important how fat the dipole is. That’s what this slide shows.

64We have 12 occurrences of WH-clefts, and 16 of RWH in our oral data. We will first examine WH-clefts, to study their role in managing information flow.

4.4.1. WH-clefts

65Pseudo clefts do not change the canonical information structure pattern theme/rheme. However the division between ‘given’ and ‘new’ is highlighted, and as a result the listener is encouraged to pay attention to the ‘new’ elements, which are given more focus.

(32) So what do I mean by pulse sharpening using non-linear ferroelectric dielectrics?
Well, what we’re talking about here is pulses in the voltage range of 10 to 40 kV with a peak current in the range of (P4)…
Given New

66This example comes right at the beginning of the talk. The information in the WH part of the cleft is presupposed. The speaker has just raised the issue, which is in fact the subject of the talk, in the preceding rhetorical question. The cleft enables him to draw attention to the forthcoming explanation. The audience is prepared and forewarned that an important explanation is imminent. Without the cleft the information would have received less impact.

The pseudo-cleft would therefore seem to have two main functions:

  • it slows down the discourse flow, chunking the information conveyed into two distinct parts, thus helping the listener to process it more easily.

  • it enables the speaker to set the stage for the new forthcoming information, thus increasing its salience.

67In other words, it clearly identifies the important information, thereby increasing its salience, and at the same time it gives the listener strict processing instructions by making it quite clear against what background a proposition has to be understood. When we compared the pseudo-clefts in the oral papers with the passages in the articles that contain the same information, we found very little explicit highlighting or focusing of this kind. Writers just give the bare facts.

68The WH-cleft could also be considered as an interactive strategy that the speaker can use to prepare his audience for the upcoming information, thus helping them to assimilate the most important points of the talk. Indeed, it seems that the presence of the WH- element implies some sort of questioning process. In the above example (32) the speaker actually asks this question himself but in many WH-clefts there would seem to be an underlying presupposed question that either the audience is likely to ask at that stage, or that the researchers asked themselves at that point.

Q [what did you do then? / What shall we do now?]

(33) so what we did here was took a lot of data with different gas pressures... (P2)

69This might help explain why WH-clefts are only found in oral data – either conversation or our conference presentations – as the interpersonal level of question and answer is much more present, even if the speaker is delivering a monologue.

4.4.2. Reverse WH-clefts

  • 7 Biber et al 1999, also refer to these constructions as demonstrative WH-clefts.

70Reverse WH-clefts, as already mentioned, are slightly more common then WH-clefts, in our oral data. What is immediately striking is that practically all have a demonstrative7 as the cleft constituent:

(34) it’s really important how fat the dipole is, that’s what this slide shows (P2)

(35) You can see the larger one in this example in cavity two compared to one and three….So that’s what the experimentalists can see (P11)

(36) This is kind of like what it all looks like in the lab (P3)

(37) This is what EMBL looks like (P2)

71However, as can be seen from the examples given here (and confirmed by the other examples in the data), THIS and THAT fulfil different functions. ‘THAT’ is anaphoric and has a resumptive function; it slows down the discourse by summing up a segment and emphasising its importance before moving on to the next new piece of information. THIS on the other hand, has a deictic function in our corpus, pointing forward to a new element of information displayed visually on the slide.

(verbal)  that this (visual)

72The fact that demonstratives are frequently used in the oral presentations for these two functions seems particularly significant: the speaker is constantly engaged in pointing, or showing, the way so that the participants can orient themselves in the discourse. THAT relates more to the verbal channel, and is used for summarising ideas expressed verbally, while THIS refers more concretely to the visual channel. Used together the judicious use of THIS and THAT reverse WH-clefts serves to integrate the two channels of communication, the visual and the verbal, and contributes significantly to the clarity of the discourse.

73Like the ordinary WH-cleft, the reverse WH-cleft helps to chunk the discourse into manageable units for the audience, and has a framing function. However, while THAT concludes a segment of discourse, THIS opens up a new segment. As with inversions, this text strategy of creating text units, or fairly short portions of texts which are clearly bounded (marked for onset and close) is dictated by the discourse context, and entails the use of certain specialised structures which are very little used in scientific writing. Written discourse is not ephemeral, and perhaps does not require these attention markers and small, intermediary summaries as the discourse progresses.

5. Conclusion

74This study has compared two scientific genres – written proceedings articles and oral conference presentations in physics – from the point of view of information structure. It clearly emerges from the study that the enunciative context, and in particular the mode, written or oral, has a strong influence on the information packaging resources used by writers and speakers. By holding constant other variables such as subject matter, author, and audience, we have shown that the mode of presentation makes a considerable difference to the way in which the subject matter is packaged and presented. The processing constraints in each mode are radically different, and as a result different information packaging strategies are required. This in turn means that different specialised structures, or the same structures used in different proportions, are needed in order to package information effectively.

75Of the four structures analysed in detail here, extraposition is the only one to occur more frequently in the written articles than in the oral presentations. It is widely employed in the articles not only as a hedging device but also as a means of facilitating information processing for the reader by enabling the given and new elements to be distributed more evenly over the sentence. In the oral presentations, in contrast, such a device is used far less frequently because it is not needed: authorial comment is expressed congruently, without recourse to extraposition for hedging, and clausal themes are considerably less complex, due to the constraints of live communication, thus obviating the need for this syntactic structure.

76The second specialised structure that is found in both modes, namely existential there, shows the opposite distribution, being far more frequent in the oral presentations than in the articles. While its traditional function of introducing a new referent into the discourse is apparent in both modes, its role as an enumeration device appears to be particularly marked in the oral presentations, where it helps the audience to follow the discourse organisation and to process sequential information. We surmised that the same role was fulfilled by typographical devices in the written article. The use of existential there in spoken and written science indicates that the same specialised structure may, therefore, be used in both oral and written modes but not necessarily in response to exactly the same information packaging needs.

77It is in the use of the remaining two structures, pseudo-clefts and inversion, that the differences in information packaging requirements between spoken and written science appear most clearly. Neither occur in the proceedings articles, but both are frequently used by speakers in their presentations. Pseudo-clefts serve to slow down the discourse flow in the oral presentations, highlighting the division between given and new information and helping the listener to focus on a particular item of information. They thereby function to segment the discourse into smaller, more manageable chunks and to indicate salience. We would therefore interpret the use of this syntactic resource as being linked to the constraints of the real-time processing of information in speech. Live communication is ephemeral in nature; as a result, the speaker needs structures which enable him to refocus the audience’s attention whenever necessary in order to ensure that they do not lose the thread of his argument. Writing, on the other hand, is not ephemeral, and so does not require such attention markers to the same extent.

78The use of inversion in the oral presentations appears to have a similar function of assigning focus to new information. In addition, this structure plays an important role in ensuring that the principle of end-weight is respected. The main reason for its frequent occurrence in scientific conference presentations, however, is the communicative context of this genre, namely the need for the speaker to integrate two channels of communication, the verbal and the visual. Inversion is the preferred structure for drawing the audience’s attention to the visual display, prior to commenting verbally on it, and for guiding the audience’s reading of the visual itself. Indeed, inversion with an initial adverbial of place is such a natural packaging strategy in this enunciative context that the very term ‘inversion’ would seem to be a misnomer.

79We believe that by studying information packaging arrangements we can gain greater insight into why, in a specific context, certain structures are preferred or dispreferred. The implications of this in pedagogical terms are numerous. The present study is in fact part of a wider project in which we intend to go on to study the differences between how native and non-native speakers package information. An initial hypothesis is that specialised structures are not always used efficiently by non-native speakers in science. Non-native speakers seem to differentiate less between written and oral modes of scientific communication, tending to overuse, in oral presentations, structures that are typical of writing such as the passive, and not to use structures that are typical of speech such as pseudo-clefts and inversion. In other words, they lack pragmatic competence. As a result, this makes their discourse much more difficult for the listener to comprehend and process. As teachers we have to show our students that scientists do not write and speak about their work in the same way. In a language of fairly fixed word order such as English, the specialised syntactic structures examined here afford a certain latitude on the discursive level, enabling the enunciator to orient or reorient the informational weight of clauses according to the effect required for a given communicative situation. Different enunciative situations require different solutions.

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Appendix 1

1. The data used in this study comprise oral presentations given at the following physics conference; the articles are from the Book of Proceedings of the same conference: Euro Electromagnetics. International symposium on electromagnetic environments and consequences. Bordeaux, May 30 – June 4, 1994.

2. The titles of the nine proceedings articles (A) and the corresponding nine oral presentations (P) are as follows:

A2 – P2

Sandia National Laboratories’ high power electromagnetic impulse sources

A3 – P3

Stacked Blumlein pulse generators: versatile sources of high power repetitive waveforms

A4 – P4

High voltage pulse sharpening using nonlinear ferrolectric ceramic dielectrics

A5 – P5

Lightweight, tactical prime power for mobile pulsed power applications

A9 – P9

The development of high peak power solid state pulse generators

A11 – P11

Milo experiments and computer simulations

A13 – P13

Low-voltage, explosive whisker emission cathode studies

A14 – P14

Efficiency enhancement of high power vacuum backward-wave oscillators driven by short pulse and long pulse electron beams

A15 – P15

Nonlinear space-charge waves in an axially uniform waveguiding structure

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1 See Appendix 1 for details of the conference and a list of the presentations and articles in the corpus. Full information about the criteria used to select the conference and the presentations can be found in Rowley-Jolivet (1998, Chap. 4: 195-223).

2 There is some interesting work on university lectures, but this is didactic discourse and therefore rather a different genre from research presentations to peers (Flowerdew 1994).

3 See Carter-Thomas (2000, Chap. 2) for a more detailed account of information structure and the interaction between syntax and information structure.

4 These figures confirm those of Banks (1995: 6-9) as far as the written corpus is concerned. Note, however that finite extraposition also dominates in our oral corpus.

5 Examples taken from the proceedings articles are referred to by the letter A plus the number of the article, and examples from the oral presentations by the letter P.

6 See Thomas (1999) for the different types of thematic progression used in scientific writing.

7 Biber et al 1999, also refer to these constructions as demonstrative WH-clefts.

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Table des illustrations

Fichier image/png, 5,8k
Titre Table 1. Quantitative comparison of conference proceedings articles and oral presentations
Légende Mean percentage is given for the passive only; it is not indicated for the other specialised structures due to the small numbers involved
Fichier image/png, 21k
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Shirley Carter-Thomas et Elizabeth Rowley-Jolivet, « Syntactic differences in oral and written scientific discourse: the role of information structure »ASp, 31-33 | 2001, 19-37.

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Shirley Carter-Thomas et Elizabeth Rowley-Jolivet, « Syntactic differences in oral and written scientific discourse: the role of information structure »ASp [En ligne], 31-33 | 2001, mis en ligne le 23 septembre 2010, consulté le 21 avril 2024. URL : ; DOI :

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Shirley Carter-Thomas

Shirley Carter-Thomas est maître de conférences à l’Institut National des Télécommunications (INT). Ses domaines d’intérêt sont l’analyse du discours spécialisé écrit et le passage de l’oral à l’écrit, la linguistique fonctionnelle et la syntaxe. Elle est membre du groupe de recherche OSTERLITS (FRE 2203) du CNRS.

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Elizabeth Rowley-Jolivet

Elizabeth Rowley-Jolivet est maître de conférences à l’Ecole Supérieure des Procédés Electroniques et Optiques, Université d’Orléans. Ses axes de recherche sont l’analyse du discours scientifique oral et le passage de l’oral à l’écrit, la communication visuelle en science et la sociologie de la science. Elle est membre du groupe de recherche OSTERLITS (FRE 2203) du

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