There is not the space in the current context to set out the engagement system in its entirety. I will confine myself therefore to exploring the valeur relationships which operate most generally. To this point, I have explored the monogloss versus the heterogloss distinction and the extra-vocalise versus the intra-vocalise distinction. In the current context I will confine myself to examining one more dimension of semantic optionality, that which operates in the context of intra-vocalisation and which turns on the distinction between what I term `open' and `close'.
Modes of heteroglossia - `open'
Figure 3: engagement - open versus close
The resources which I include under `open' can be understood as acting to `open up' the heteroglossic dialogue, to extend the text's potential for construing heteroglossic diversity. There are three closely interrelated options by which the potential for construing heteroglossic diversity can be extended - under `probability' (modality), under `appearance' (reality phase Halliday 1994: 279-83)) and under hearsay (see Figure 3 above).
The semantics of probability and appearance (reality phase) are widely referenced in the literature. As discussed above, under the heteroglossic perspective, meanings such as `I think ...', `probably', `It seems...', `Apparently ...' etc are not construed as evasions of truth values but rather as resources by which the speaker `opens up' their potential for interacting with the heteroglossic diversity.
The second option under `open', `appearance', serves a similar rhetorical function to probabilise. It `opens up' the potential for negotiating the heteroglossic diversity by reference not to probability but by foregrounding and making explicit the evidential process upon which all propositions rely.
The final option under `open' - `hearsay' - entertains heteroglossic diversity in a similar way, although its semantics perhaps require some additional explication. Under `hearsay' the possibility of heteroglossic alternation remains open because the utterance is marked as based on what some unspecified person said. In many languages, of course, hearsay is coded grammatically rather than lexically - hearsay is an integral part of the modality system. Within English and similar languages, hearsay is coded by means of wordings which derive from the grammar of verbal projection but in which the projecting sayer is absent or cannot be specified - thus, `Reportedly, she viewed the papers', `Her alleged viewing of the documents.', `It's said she viewed the papers.', `I hear she viewed the documents.'. The semantic consequence of such structures is not to introduce an alternative voice into the text and hence `hearsay' is included within `intra-vocalise' and not within `extra-vocalise'. Rather, it functions to indicate that the meanings qualified by the hearsay are negotiable in heteroglossic terms.
There are a number of grammatical grounds for, firstly, identifying `hearsay' as a distinct discourse semantic category separate from the extra-vocalisation categories which it superficially resembles and, secondly, for aligning it in the semantics with `probability' and `appearance'.
`Hearsay' is like `probability' and `appearance' in that it too may be realised via comment adjunct - possibly (probability), seemingly (appearance), reportedly (hearsay). This indicates that `hearsay' is an interpersonal coloration which may be applied prosodically to the clause in its entirety. As well, under the lexico-grammatical diversification discussed previously, both `probability' and `appearance' may be realised by a range of lexico-grammatical structures _ by adverbs (comment adjuncts) such as possibly and apparently, by relationals such as it's certain that .., it's apparent that and by verbal forms such as I think he ..., he may ..., it seems that.. and he seems to ... . `Hearsay' is realisable through a similar range of choices _ thus the adverbial reportedly, the adjectival his reported decision to resign, and the verbal, it's said he.. It is also noteworthy that this verbal form, it's said that, shares key grammatical features with I think that. Halliday has demonstrated what he terms the grammatical metaphorical status of I think ... structures (Halliday 1994 chapter 10). (These metaphors have been discussed previously in section II.3.(b).6. I briefly review those arguments here for the sake of ease of reference.) He argues for the metaphorical status of I think... on the grounds of the way such structures respond to tagging. 'I think the Premier saw the documents' typically tags for the Subject of the dependent projected clause ('I think the Premier saw the documents, didn't she?') rather than for the ostensive subject of the clause complex (?? 'I think the Premier saw the documents, don't I?'). Thus Halliday concludes that the projecting I think is not, in fact, the source of the clause-complex's modal responsibility, acting, instead, in the manner of a modal adjunct such as perhaps or possibly to probabilise the utterance. The hearsay structure, I hear..., displays similar though not identical grammatical anomalies which provide a basis for viewing it as similarly 'metaphorical'. Most notably, with the hearsay value, the present tense is used for a past event (the act of hearsay occurred in the past) - thus 'I hear she decided to leave' versus 'I heard that she decided to leave.' Additionally, 'I hear' structures do not tag for the ostensive Subject _ ?? 'I hear that she decided to leave, don't I?'
