The relations between nexion and information structure (alias functional sentence perspective) are both on the paradigmatic and on the syntagmatic axis.
- On the one hand, information structure just as nexion has to do with the articulation of a complex thought into elementary propositions. While nexion deals with the syntagmatic semantic relations among the component propositions, information structure deals with information status relations among them (presupposition – assertion, focus – background etc.). Both kinds of semantic entities and relations among them, are, however, coded in the form of complex sentences.
- On the other hand, the complex sentences produced in nexion are, in their turn, subject to structuring in terms of information structure (just as the expressions produced in most other functional domains are). In this sense, these two domains also interact syntagmatically.
In principle, distinctions in terms of information structure are clearest at the highest levels of syntactic complexity, i.e. at the text level and the level of the (complex) sentence. The lower the syntactic level, the more such distinctions are levelled out. Consequently, while a complex sentence is clearly structured in terms of information relations, this is much less the case inside a subordinate clause. The more a subordinate clause is reduced (see Reduction and expansion of clauses), the less can it distinguish relations of information structure. Consequently, the extent to which they allow for an information structure of their own is one of the criteria by which subordinate clauses may be classified.
In French, for instance (Lahousse 2008), adverbial clauses in general allow for verb inversion. However, they fall into two groups by the criterion of whether this is exclusively triggered by information structure or may be conditioned by other factors.
- In causal (parce que, puisque) and concessive clauses (bien que), the former is the case,
- while in temporal (quand, pendant que), comparative (comme), purpose clauses (pour que, afin que) and negative circumstance clauses (sans que), the latter is the case.
The former group is, at the same time, the set of subordinate clauses that may be marked for an epistemic modality of their own (peut-être, probablement). The proposition of these subordinate clauses is challengeable, whereas the proposition of the latter is not. Challengeable subordinate clauses are, thus, more similar to main clauses than non-challengeable ones.