Inflectional Suppletion and Heteroclite Inflection from a Diachronic Perspective

Inflectional suppletion can emerge by three distinct mechanisms, regular sound change, grammaticalisation of derivational patterns, and conflation of originally independent lexemes into one. While the former two mechanisms do not raise questions going beyond historical phonology and grammaticalisation theory, the third mechanism constitutes a mystery. Why two originally independent lexemes sometimes conflate into one and what may govern their distribution in the new suppletive paradigm – both these questions are still awaiting a comprehensive investigation. The major obstacle in the way of such an investigation is the insufficient amount of high‐quality data, i.e. instances of inflectional suppletion whose starting point is either directly documented in texts or can be securely inferred from closely related languages. The paper argues that this problem can be partly overcome by taking into consideration a special kind of non‐canonical inflectional suppletion which is known as heteroclite inflection or heteroclisis. The differences between canonical inflectional suppletion and heteroclisis seem to be confined to their synchronic status within the grammar and to their potential productivity. These differences are irrelevant when the emergence of inflectional suppletion is under consideration. Taking into account the heteroclite inflection has the potential to considerably enlarge the empirical basis of any investigation into the emergence of inflectional suppletion. This is especially important for establishing factors governing the constituent distribution in suppletive paradigms and investigating the role played by pre‐existing non‐suppletive patterns of alternation. It might also be hoped that investigating heteroclisis as inflectional suppletion will help address the semantic relations between lexemes about to merge in a more systematic way.