As explained suo loco, junction may be conceived as the grammaticalized counterpart of a subdomain of discourse structure, viz. rhetorical structure. Consequently, junction subsumes a variety of ways in which two propositions united in a complex proposition may be related to each other:

Enunciative relation

An enunciative relation constitutes a situation of speech reproduction. If this configuration is grammaticalized, the enunciative relation becomes an intrinsic interpropositional relation.

Interpropositional relation

Given two propositions p and q adjacent in a discourse but not connected by an enunciative relation, then an interpropositional relation may obtain between them. The relation may then be intrinsic to (a component of) p; or may be coded by an interpropositional relator whose arguments are p and q.

Interdependence of time reference and aspectuality

Starting from the supposition that junction combines two propositions, these may, in principle, be independent in their time reference and aspectuality. Such mutual independence may materialize in some types of complex sentences, for instance conditional constructions. Often, however, the interpropositional relation will constrain the choice of tense and aspect in the dependent clause.

In direct perception, the two situations are simultaneous.

The time reference of a consecutive and a purpose clause must be after the time reference of their matrix clause.

The temporal and aspectual relation between the two propositions is typically coded by the interplay of an interpropositional relator with a specific combination of tenses and aspects of the two clauses.

• Some languages (like German) code the bulk of this information in the conjunction. For instance, a conjunction meaning ‘while’ may imply imperfective aspectuality in its clause; but in German no such aspect is coded, so the conjunction (während) alone conveys this information ().
• In other languages (like Yucatec Maya), the subordinator itself may be semantically empty, the specific temporal relation being brought out only by the tenses and aspects of the two clauses ().

There is no connective in to indicate a simultaneous temporal relation (káa is a functionally neutral clause connective).

Interdependence of time reference may grammaticalize to a constraint on consecutio temporum.

Interdependence of participant reference

Empty place control

A subordinate proposition may contain an empty position – typically, but not necessarily an argument position – which is conceived as being occupied by a referent or concept present in the context.

Subject control has been mentioned for the purpose relation; it is, however, relevant to other interpropositional relations, too.

Given a neurological constraint on parallel processing in humans, there is a general tendency (Nishina 2004) to the effect that

• simultaneous situations have distinct actors
• subsequent situations have the same actor.

Interdependence of participant reference may grammaticalize to a constraint on empty place formation.

Concept anchoring

A concept may be enriched by the involvement of its referent in a situation coded by a proposition. This is dealt with suo loco.

Information status of the propositions

One of the properties of propositions relevant in the present connection is the status of the two propositions in terms of the dichotomy of ‘assertion vs. presupposition’. In this connection, a proposition – in particular, a subordinate proposition – may be:

• factive (presupposed),
• non-factive:
  1. independently asserted;
  2. unreal/potential

More on this in the section on mental state relations between superordinate and subordinate proposition.