The following is based on Hengeveld 2007.
Semantics
Given a superordinate proposition p and a subordinate proposition q, then if q is an argument of a predicate of p, q may be coded as a complement clause. Q may or may not then be presupposed by the speaker. For instance, in Linda regretted that q, the speaker presupposes q, while in Linda said that q, he does not presuppose q.
If q is not an argument of p, but instead bears some modifying relation to p, it is more commonly presupposed and coded as an adverbial clause. But even in that case, q may constitute the content of a mental state of the agent of p. In the following, this is investigated with modifying clauses that differ in the temporal relation between p and q.
The two criteria of the presence or absence of a mental state relation between p and q, on the one hand, and of the temporal relation between p and q, on the other, distinguish the essential subtypes of mental state relation constructions for adverbial clauses:
mental state relation
temporal relation | no | yes | |
|---|---|---|---|
| p precedes q: yes | cause | reason | |
| no | q lasts up to p: yes | end-point | intended end-point |
| no | consequence/result | purpose | |
The table thus provides a semantic systematization for some of the traditional adverbial clause types.
Coding
In the adverbial clauses of the above table, presupposition of q is the default. The speaker cancels the presupposition, ascribing responsibility for q to the agent of p, by special coding. The structural means employed comprise the following:
- The mood of the subordinate clause of the right-hand column of the table indicates that q is the content of a mental attitude of a participant of the superordinate proposition.
- The subordinative conjunction of the clause of the right-hand column signals the relation to the main clause agent, e.g. by an etymology related to reported speech.
These adverbial clauses are similar to complement clauses semantically to the extent that they encode a participant's mental attitude towards their proposition, and they are similar to them formally by using similar conjunctions and moods.
Reference
Hengeveld, Kees 2007, "The status of purpose, reason and intended endpoint in the typology of complex sentences, and its implications for layered models of clause structure." Linguistics 45:000-000.