On the directionality from temporal to conditional

Abstract

Abstract This paper examines the purportedly unidirectional process from temporal connective to conditional connective. As conditionals developed into temporals and vice versa in Chadic languages, Japanese and Mandarin, unidirectionality in the strict sense is unlikely, even though conditionals are more grammatical than temporals. As the bidirectional changes likely originated in contexts where formal and functional equivalence held between temporals and conditionals and their morphosyntactic distinction was vague, it is proposed that the changes are regular processes mediated by morphosyntactic vagueness. The proposal thus suggests that grammatical change may be regularly bidirectional. Grammaticalization, if defined in terms of regularity rather than unidirectionality, may be bidirectional, too.