Marking of causal relationships
In a sentence describing two related events, the reason clause offers the causal explanation of their relationship. This element of the sentence may contain a finite verb, a nonfinite verb, or another verb-derived word class. A reason clause may also include adjuncts. Causal markers are the grammatical strategies, whether independent words, affixes, particles, or special verb forms,1 that are optionally or obligatorily used to mark reason clauses, in contrast to simple declarative sentences. This scope of this parameter is restricted to strategies that only appear with a causal function.2
Types:
NoCauseMark: No grammatical strategies are used to a mark reason clauses; the causal relationship between the two events can be determined by contextual or pragmatic clues.
CauseV: Causal relationships are marked by a special verb form in the reason clause.
CauseAff: Causal relationships are marked by a special affix on the verb in the reason clause.3
CauseClit: Causal relationships are marked by a special clitic in the reason clause.4
CauseWV1: Causal relationships are marked by an independent word in the main clause.5
CauseWV2: Causal relationships are marked by an independent word (conjunction) in the reason clause.
When a language displays more than one type, two values can be listed. If one type is dominant, a slash (/) can separate the two values, with the dominant value appearing first; if neither is dominant, they are listed with an ampersand (&) separating the two. The use of parentheses indicates that strategy is not obligatory, while the use of a plus sign (+) instead of an ampersand indicates that the two strategies must be used simultaneously.
1: Special verb forms refer to “demoted” verbs, which are originally derived from a verb but now function as a different word class. Examples include gerunds, converbs, and participles. Special verb form also includes finite verbs that differ from the base form in their marking of person, case, cause, mood, or aspect or in their co-occurrence with adpositions.
2: For example, modal verb forms are only considered if their exclusive function is the expression of causal relationships.
3: The special morpheme should be invariant (non-paradigmatic) in its form. Without it, the verb form would be identical to the form in which it appears in an independent clause.
4: The clitic should be invariant (non-paradigmatic) in its form and does not necessarily attach to the verb. Without it, the verb form would be identical to the form in which it appears in an independent clause.
5: This covers cases in which the sentence is not complex and those in which the marker appears obligatorily in the main clause rather than the reason clause. The word class of the independent word should be specified in the commentary.