From a motion verb to a temporal gram: The case of Nkami

This paper explores the grammatical pathway through which the future tense marker bɛ̀ - evolved in Nkami, a lesser-studied Kwa language of Ghana. The analysis is based on synchronic natural data drawn from an extensive corpus collected during a language documentation project focusing on both the language and its speakers. It reveals that Nkami’s future tense marker evolved from the deictic motion verb bɛ̀ɛ̀‘come’ along the following channel: bɛ̀ɛ̀ (lexical verb) →bɛ̀- ‘proximal directional prefix’ → bɛ̀- ‘future tense prefix’. This derivation strengthens a widely held observation that (deictic) motion verbs are a rich source concept for deriving grammatical markers of temporal orientation. Besides developing into grammatical items, the paper also shows that bɛ̀ɛ̀developed into another form, bà, which co-exists with it to express the lexical concept of ‘come’. Apart from indicating the deictic motion ‘come’, bà/bɛ̀ɛ̀also complements bʊ ‘have’ to express property in completive situations, which contrasts with the general tendency to use the verb ‘do’ in such situations. Principles of grammaticalization, including polygrammaticalization, divergence, persistence, and decategorization, are all shown to be relevant in the evolution of the future tense marker in Nkami. Lastly, the investigation into the grammaticalization of the future tense marker in Nkami provides additional support for classifying Guang (Kwa, Niger-Congo) languages into Northern and Southern groups.