Routes towards the irrealis

Irrealis markers are characterized by the rampant heterogeneity of their distributional patterns and by the tendency to appear as portmanteau morphemes encoding other grammatical categories (e.g. person). These and other characteristics may find an explanation in diachronic terms, by taking into account the sources from which irrealis markers derive. In this paper, the most frequent sources of irrealis markers are identified by means of a diachronic-typological survey based on a 100–language sample: these include lexical verbs such as ‘go’, ‘want’ or ‘be’, former subordinate clauses that come to
be used as main clauses through insubordination and deictic expressions that refer to distant elements. Considering the diachrony of irrealis markers allows us to explain some of their properties such as, among others (i) their distribution across the domain of non-actualized situation types, (ii) the primacy of certain non-actualized situation types that happen to work as bridgeheads in the diachronic development from the source to the target irrealis marker, (iii) the frequent co-encoding of person and reality status by means of the same markers, and (iv) the existence of ergativity splits involving irrealis
clauses. The diachronic-typological survey conducted in this paper has some implications on the debate on the validity of reality status as a grammatical category with two opposite values of realis and irrealis: it will be argued that the diachronic scenarios leading to the emergence of irrealis markers are not substantially different from those known from the literature on the emergence of modal markers, which makes reality status superfluous as an independent grammatical category.