Making sense of irregular realisations of the past tense suffix in Northern Sotho: the phonology-morphology interface

Abstract

Descriptions in Northern Sotho textbooks of past tense formation and the many alternations of the past tense suffix have traditionally been based on the phonological environment to which *-ilê is affixed. Explanations were never offered as to why, within the same phonological environment, the past tense suffix could realise different past tense forms. The realisation of more than one form in similar phonological environments has been interpreted as exceptions. Following on the valuable contribution of Bastin (1983), this article illustrates how, when affixed to similar vowel-consonant phonological environments constituted by simple stem material versus an extension occurring in a stem, the past tense suffix in Northern Sotho reacts differently. This is seen as indicating that simple verb stems and extended verb stems were historically treated differently during past tense formation. Although the boundaries between the two strategies that were followed have become blurred due to analogy and lexicalisation, there is ample language data to support this notion. The research reflected in this article was aimed at building a lexical transducer for the formation of Northern Sotho past tense verbs and serves to augment rather inadequate existing grammatical descriptions of past tense formation.