To describe coherence in a text, topical structure analysis, which Lautamatti (1978) developed from the topic-comment theory of the Prague School of Linguistics, inspects the semantic relationships between sentence topics and the overall discourse topic by investigating the repetitions, shifts, and reoccurrences of topic. In this essay, coherence is taken to be, following van Dijk (1977: 93), a semantic property of discourse formed through the interpretation of each individual sentence relative to the interpretation of other sentences.1 Interpretation implies interaction between the text and the reader, and it is within this theoretical perspective, as opposed to focusing solely on the text, that this study as well as the studies of Witte and Schneider and Connor take place. 2
The Prague School linguists laid the foundation for topical structure analysis by first distinguishing theme from enunciation. According to Witte (1983a), Vilem Mathesius used the term theme to identify "what the sentence is about" and the term enunciation to refer to "what is said about" the theme. In a point relevant to my later discussion of the theoretical basis for topical structure analysis, Mathesius maintained that "the theme of a sentence announces 'what is known or at least obvious in a given situation and from which the speaker proceeds in his discourse,' while enunciation adds new or unknown information to the discourse,"3 a distinction that has also been cast in terms of given and new information. Over time the term enunciation gave way to rheme, and rheme to comment. The term theme, meantime, changed to topic, following the usage of Charles Hockett. I will use the term topic to refer only to sentence topic, which is distinct from discourse topic.
The concept of discourse topic also emerged from the theoretical framework of the Prague School linguists. In particular, as Witte (1983a) points out, Frantisek Danes showed that topics of successive sentences can be identified in relation to what Danes called a "hypertheme," in effect a discourse topic, which may or may not be explicitly stated in the text. The discourse topic is what the text, taken as a whole, is about.
Lautamatti (1978) demonstrates the relationship between sentences in a text and discourse topic. Sentence topics, which are units of meaning organized hierarchically in the text, make a semantic contribution to the development of the discourse topic. Lautamatti (1978: 71) puts it thus:4
"The development of the discourse topic within an extensive piece of discourse may be thought of in terms of a succession of hierarchically ordered subtopics, each of which contributes to the discourse topic, and is treated as a sequence of ideas, expressed in the written language as sentences. We know little about restrictions concerning the relationship between sentences and subtopics, but it seems likely that most sentences relating to the same subtopic form a sequence. The way the written sentences in discourse relate to the discourse topic is ... called topical development of discourse."
The sequences of sentences, Witte (1983a: 319) writes, advance the "discourse topic by developing a succession of sentence topics, sequences that Lautamatti calls topical progressions," which help describe how individual sentences cohere locally and how all sentences within a text cohere globally. Connor (1996) shows that coherence can be mapped using a system of three distinct progressions:
The relationship between the progression of sentence topics and the semantic hierarchy of a text is captured in Lautamatti's notion of topical depth. Lautamatti maintains that the sentence topic stated first in an extended text is frequently at the highest level in the semantic hierarchy. Lautamatti combines the concepts of topical progression and topical depth to represent a text's topical structure in a topical structure analysis.
Connor and Farmer (1990) explain how to conduct a topical structure analysis. In this section, I will summarize their approach and present a brief example analysis, as later in this essay I will use their approach to provide a detailed topical structure analysis of 15 accomplished essays.
The point of departure for conducting a topical structure analysis is the distinction between topic and comment. Topic is the main idea of the sentence – what the sentence is about – which often coincides with the sentence's grammatical subject:
John exercises every day.
The topic, however, is not necessarily the grammatical subject. Since topic is a semantic property, that is, a unit of meaning, whereas grammatical subject is a syntactic property, some divergence between the two occurs, as the italicized topic in these examples from Huddleston (1984: 59) shows:
In Queensland one can swim in the sea all year round.
Close tabs are being kept on all the radical students.
In other cases, the topic not only includes the lexical unit that makes up the grammatical subject but also spans other parts of the noun phrase in which the subject is located, as the italicized topic in the following example demonstrates:
The concepts of 'theme' and 'rheme' or ''given' and 'new' information in sentences grew out of Mathesius’ work.5
The noun or noun phrase that typically expresses the topic, which is determined in part by the context, may occur at the beginning, middle, or even end of a sentence. Examples:
The earth evolves around the sun.
Biologists and linguists agree that language is an important species-specific property.
Close tabs are being kept on all the radical students.6
I discuss the methodological issues associated with identifying topics in a later section.
Comment, according to Hockett, refers to what is said about the topic. Just as the topic is often the grammatical subject, the comment is often but not necessarily the grammatical predicate:
Mathesius attempted to explain the relationship of individual sentences within the context of extended texts.
The Federal Election Commission has a duty to condemn and punish the illegal fund-raising by President Clinton and Bob Dole during the 1996 election.
Executing a topical structure analysis involves identifying topics and relating them to previous sentential topics as well as the discourse topic. Witte (1983a: 341 n. 50) identified topic by asking "what is this sentence about?" and moving "from one noun phrase to the next until I found what I thought was a satisfactory answer for each sentence in the context of the whole discourse." Schneider and Connor's study also identified topic by asking what the sentence is about. My analyses below strive to use largely the same approach as that of Schneider and Connor, enabling me to compare my findings with theirs.
The relations of sentential and discourse topics are charted using the three kinds of topical progression detailed above. The first step in the analysis is to identify and underline all the sentence topics in the text. The second step is to construct a diagram corresponding to the topical structure of the essay. The diagram, Connor and Farmer explain, is constructed by placing sentence topics with parallel progression exactly below each other. Sequential topics are indented progressively. A topic with extended parallel progression is lined up under the parallel topic to which it refers. When a chart is made to show the topical structure of a text, the progressive indenting represents topical depth. The following chart of a short newspaper editorial illustrates this method for conducting a topical structure analysis:
1 Federal Election Commission
2 both candidates [ref=Clinton and Dole]
3 both [ref=Clinton and Dole]
4 the party
5 ambiguity
6 explicit language
7 the Democratic ads
8 Mr. Clinton
9 they [the federal election commissioners]
10 the lawsIn this chart, the progressive indentation that sets Line 2 off from Line 3 indicates a sequential progression. The vertical alignment of Line 3 with Line 2 indicates that the topic in Line 3 is a parallel progression. Meantime, the vertical alignment of Line 9 with Line 1 indicates an extended parallel progression. For convenience, in Lines 2 and 9 I have included the referents of the topics in brackets.
Diagrams and Examples of Topical Structure Analysis
The Three Topical Progressions
How to Diagram Topical Progressions