A when-construction describes two events that have some form of temporal, whether co-, sequential, or logical occurrence. In this type of construction, one of the two events is described in a phrase or clause that serves to answer the question When? This construction can appear as either (a) a verb or word derived from a verb or (b) a subordinate clause containing a finite verb (when-clause). A when-clause marker is an obligatory or optional strategy used to mark a clause as a when-clause, and it may appear as an independent grammatical word, affix, particle, or special verb form that would not appear in a simple declarative sentence. Only strategies specific to when-clauses should be considered.
NoWhenMark: When-clauses are not marked as such. The two events are described in juxtaposition, and the temporal relationship between them must be inferred logically or based on contextual cues.
WhenV: When-clauses are marked by the use of a special verb form.
WhenAff: When-clauses are marked by the use of a special verbal affix.
WhenClit: When-clauses are marked by the use of a special clitic.
WhenWV1: When-clauses are marked by the use of an independent word (referent) within the main clause.
WhenWV2: When-clauses are marked by the use of an independent word (conjunction) within the 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. Parentheses indicate that use of the strategy is not obligatory.
 Special verb forms refer to “demoted” verbs or nonfinite verb forms originally derived from a verb. Examples include gerunds, converbs, and participles. Special verb forms also include finite verbs that differ from the base form in their marking of person, cause, mood, or aspect or in their co-occurrence with case markers or adpositions.
 For example, tense harmony is only considered a when-clause marker if its use is exclusive to marking when-clauses.
 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. In some cases, the special morpheme may appear as an affixed conjunction required in any subordinate clause.
 The clitic should be invariant (non-paradigmatic) in its form and does not necessarily attach to the verb. Without it, the sentence would be identical to its independent clause version.
 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 when-clause. (Optional use does not qualify.) The word class of the obligatory independent word should be specified in the commentary.