The Grammatical Function Of The Tone Group

Halliday & Matthiessen (2014: 115):

… the tone group functions grammatically as realisation of a quantum of information in the discourse. It is this quantum of information that we have called the information unit. Spoken English unfolds as a sequence of information units, typically one following another in unbroken succession – there is no pause or other discontinuity between them.

The Information Unit

Halliday & Matthiessen (2014: 115):

[information] is a system not of the clause, but of a separate grammatical unit, the information unit. The information unit is a unit that is parallel to the clause and the other units belonging to the same rank scale as the clause.

• clause 
• group/phrase 
• word 
• morpheme

Since it is parallel with the clause (and the units the clause consists of), it is variable in extent in relation to the clause and may extend over more than one clause or less than one clause; but in the unmarked case it is co-extensive with the clause.

Managing The Discourse Flow Structurally: Theme & Information

Halliday & Matthiessen (2014: 114-5):

Below the clause complex, the grammar manages the discourse flow by structural means; and here there are two related systems at work. One is a system of the clause, viz. THEME; this we have been discussing throughout the present chapter so far. The THEME system construes the clause in the guise of a message, made up of Theme + Rheme. The other is the system of INFORMATION.

The Resources For Creating Discourse Within The Grammar

Halliday & Matthiessen (2014: 114):

These textual resources are of two kinds: (i) structural; (ii) cohesive. What this means is as follows.  The grammar construes structural units up to the rank of the clause complex …; there it stops. But although the grammar stops here, the semantics does not: the basic semantic unit is the text … .  So the grammar provides other, non-structural resources for managing the flow of discourse: for creating semantic links across sentences — or rather, semantic links which work equally well either within or across sentences. These latter are referred to collectively under the name of cohesion …

The Textual Component Within The Grammar

Halliday & Matthiessen (2014: 114):

… the resource for creating discourse — text that ‘hangs together’, with itself and its context of situation.

Theme + Rheme Structure

Halliday & Matthiessen (2014: 114):

the Theme + Rheme structure is not so much a configuration of clearly bounded constituents as a movement running through the clause; this is one perspective which it is useful to keep in view.

Deicticity And Thematicity

Halliday & Matthiessen (2014: 113-4):

The WH- element in turn is part of a wider set embracing both WH- and TH- forms, which taken together fulfil a deictic or ‘pointing out’ function …

The generalisation we can make here is that all deictic elements are characteristically thematic …

The Commonality Of ‘Interrogative’ And ‘Relative’

Halliday & Matthiessen (2014: 113):

Thus all WH- groups and phrases have this dual function: on the one hand, as an element in the experiential structure; on the other hand, as marker of some special status of the clause, interrogative (mood) or relative (dependence).  These two values, interrogative and relative, are themselves related at a deeper level, through the general sense of ‘identity to be retrieved from elsewhere’; the ‘indefinite’ ones illustrate a kind of transition between the two …

The category of WH- element opens up this semantic space, of an identity that is being established by interrogation, perhaps with an element of challenge or disbelief; or put aside as irrelevant; or established relative to some other entity.

WH- Relative Items And Topical Theme

Halliday & Matthiessen (2014: 112n):

The textual Theme of a relative element is inherently thematic; in this respect, it is like other structural Themes – binders and linkers. Consequently, the topical Theme part is also inherently thematic; but since it is inherent, it seems that it leaves some potential for other experiential elements to follow the WH- element, preceding the Finite.

The Twofold Thematic Value Of WH- Relative Items

Halliday & Matthiessen (2014: 112):

Like WH- interrogatives, WH- relatives are also characteristically thematic — the group or phrase in which they occur is the unmarked Theme of a relative clause; and similarly they combine topical with a non-topical function, in this case textual …

The Twofold Thematic Value Of WH- Interrogative Items

Halliday & Matthiessen (2014: 112):

… they are at the same time both interpersonal and topical — interpersonal because they construe the mood, topical because they represent participant or circumstance.

How To Identify Theme

Halliday & Matthiessen (2014: 112):

… the Theme of a clause extends from the beginning up to, and including, the first element that has an experiential function — that is either participant, circumstance or process. Everything after that constitutes the Rheme.

Theme Summary

Halliday & Matthiessen (2014: 111-2):

(i) Initial position in the English clause is meaningful in the construction of the clause as message; specifically, it has a thematic function.

(ii) Certain textual elements that orient the clause within the discourse, rhetorically and logically, are inherently thematic.

(iii) Certain other elements, textual and interpersonal, that set up a semantic relation with what precedes, or express the speaker’s angle or intended listener, are characteristically thematic; this includes finite operators, which signal one type of question.

(iv) These inherently and characteristically thematic elements lie outside the experiential structure of the clause; they have no status as participant, circumstance or process.

(v) Until one of these latter appears, the clause lacks an anchorage in the realm of experience; and this is what completes the thematic grounding of the message.

Non-Topical Themes And The Markedness Of Topical Theme

Halliday & Matthiessen (2014: 111):

We could set up a paradigm as follows, showing the effect of different initial selections in the clause:

1. no non-topical Theme, 
2. with inherently thematic non-topical Theme,
3. with characteristically thematic non-topical Theme;

it will be seen that the marked topical Theme becomes as it were more and more marked at each step.

Argument For Thematic Status

Halliday & Matthiessen (2014: 111:

The fact that we do find clauses such as unfortunately protein you can’t store, with marked topical Theme in such an environment, shows that the experiential element following the interpersonal Adjunct still carries thematic status — otherwise there would be no sense in fronting it. This in turn means that an ordinary unmarked Theme under the same conditions is just that — an unmarked topical Theme.

Interpersonal Themes: Characteristically Thematic

Halliday & Matthiessen (2014: 110):

If there is a Vocative in the clause, or a modal or comment Adjunct, it is quite likely to be thematic: these items are characteristic of dialogue, in which the speaker may be calling the attention of the listener, or else expressing his or her own angle on the matter in hand, whether probable, desirable and so on, and hence they tend to be brought in as key signature to the particular move in the exchange – in other words, as Theme of the clause.

Conjunctive Adjuncts: Characteristically Thematic

Halliday & Matthiessen (2014: 110):

The conjunctive Adjuncts (often called ‘discourse Adjuncts’), as noted above, cover roughly the same semantic space as the conjunctions; but whereas conjunctions set up a grammatical (systemic-structural) relationship with another clause, which may be either preceding or following, the relationship established by conjunctive Adjuncts, while semantically cohesive, is not a structural one (hence they can relate only to what has gone before). These Adjuncts often are thematic; but they do not have to be. We may have either therefore the scheme was abandoned, with therefore as textual Theme, or the scheme was therefore abandoned, with therefore falling within the Rheme.  Note how the Theme + Rheme analysis enables us to explain the difference in meaning between pairs of agnate clauses such as these.

Continuatives, Conjunctions And The Quantum Of Thematicity

Halliday & Matthiessen (2014: 110):

By the same token, however, since these items are thematic by default, when one of them is present it does not take up the full thematic potential of the clause in which it occurs. What follows it will also have thematic status, almost if not quite as prominently as when nothing else precedes. We can demonstrate this by reference to the concept of ‘marked (topical) Theme’. On the one hand, after a continuative or a conjunction it is still possible to introduce a marked type of topical Theme, either in contrast or as a setting ... On the other hand, such marked Themes appear to be slightly less frequent when there is some inherently thematic item in the clause, suggesting that some of the ‘quantum of thematicity’ has already been taken up.

Inherently Thematic: Continuatives & Conjunctions

Halliday & Matthiessen (2014: 109):

Those that are inherently thematic are the (textual) continuatives and conjunctions.  As the language evolved, they have, as it were, migrated to the front of the clause and stayed there. Essentially they constitute a setting for the clause (continuative), or else they locate it in a specific logical-semantic relationship to another clause in the neighbourhood (conjunction). In either case, their thematic status comes as part of a package, along with their particular discursive force.

The Thematic Function Of Textual And Interpersonal Themes

Halliday & Matthiessen (2014: 109):

Why do these items favour thematic position in the clause – or, to put the question more meaningfully, why are they associated with thematic function, either characteristically or, in some cases [continuatives and conjunctions], inherently? In the most general sense, they are all natural Themes: if the speaker, or writer, is making explicit the way the clause relates to the surrounding discourse (textual), or projecting his/her own angle on the value of what the clause is saying (interpersonal), it is natural to set up such expressions as the point of departure. The message begins with ‘let me tell you how this fits in’, and/or ‘let me tell you what I think about this’.

Elements Serving As Interpersonal Theme [Defined]

Halliday & Matthiessen (2014: 108):

1. [interpersonal] Vocative. This is any item, typically (but not necessarily) a personal name, being used to address.
2. [interpersonal] Modal/comment Adjunct. These express the speaker/writer’s judgment on or attitude to the content of the message.
3. [interpersonal] Finite verbal operator. These are the small set of finite auxiliary verbs construing primary tense or modality; they are the unmarked Theme of yes/no interrogatives.

Elements Serving As Textual Theme [Defined]

Halliday & Matthiessen (2014: 107-8):

1. [textual] continuative. A continuative is one of a small set of words that signal a move in the discourse: a response, in dialogue, or a new move to the next point if the same speaker is continuing. The usual continuatives are yes no well oh now.
2. [textual] conjunction. A conjunction is a word or group that either links (paratactic) or binds (hypotactic) the clause in which it occurs structurally to another clause. Semantically, it sets up a relationship of expansion or projection;
3. [textual] conjunctive Adjunct (‘discourse Adjunct’). These are adverbial groups or prepositional phrases that relate the clause to the preceding text: they cover roughly the same semantic space as conjunctions.

Interpersonal Themes

Halliday & Matthiessen (2014: 107):

… modal/comment Adjunct ['modal Theme'] … vocative … finite verbal operator [in yes/no interrogative]

Textual Themes

Halliday & Matthiessen (2014: 107): 

… continuative … conjunction ['structural Theme']… conjunctive Adjunct …

Topical Theme

Halliday & Matthiessen (2014: 105):

The guiding principle of thematic structure is this: the Theme contains one, and only one, of these experiential elements. This means that the Theme of a clause ends with the first constituent that is either participant, circumstance or process. We refer to this constituent, in its textual function, as the topical Theme.

Theme, Mood & Markedness

Halliday & Matthiessen (2014: 104-5):

Thus the question which element of the clause is typically chosen as Theme depends on the choice of mood.  The pattern can be summarised as shown in Table 3-2.  When some other element comes first, it constitutes a ‘marked’ choice of Theme; such marked Themes usually either express some kind of setting for the clause or carry a feature of contrast. Note that in such instances the element that would have been the unmarked choice as Theme is now part of the Rheme.

Blogger Comment:

Note that this means that when a clause has a marked Theme, it does not have an unmarked Theme as well.  The misunderstanding that a clause can have both a marked and unmarked Theme — along with many other theoretical misunderstandings — can be traced to Martin (1992).

Adjunct As Marked Theme In Imperative Clauses

Halliday & Matthiessen (2014: 103, 104):

Imperative clauses may have a marked Theme, as when a locative Adjunct is thematic in a clause giving directions … The adjunct part of a phrasal verb may serve as marked Theme in an imperative clause with an explicit Subject, as in Up you get! … .

Predicator As Theme

Halliday & Matthiessen (2014: 103):

The imperative is the only type of clause in which the Predicator (the verb) is regularly found as Theme. This is not impossible in other moods … but in such clauses it is the most highly marked choice of all.

Unmarked & Marked Theme In Negative & Positive Imperative Clauses

Halliday & Matthiessen (2014: 103):

… the principle is the same as with yes/no interrogatives: the unmarked Theme is don’t plus the following element, either Subject or Predicator. Again there is a marked form with you, … where the Theme is don’t you. There is also a marked contrastive form of the positive, … where the Theme is do plus the Predicator … .

Unmarked Theme In ‘You’ Imperative Clauses

Halliday & Matthiessen (2014: 103):

… although the ‘you’ can be made explicit as a Theme … this is clearly a marked choice; the more typical form is … with the verb in thematic position. … here, therefore, it is the Predicator that is the unmarked Theme.