This question concerns a phonologically bound verbal marker that signals that the verb has an instrument. In some languages, applicative markers may be used to topicalize, focalize or background the instrument. This type of marking also counts for this feature. The marker could be analyzed in the language-specific case as voice, indexing or a ‘bound pronoun’. The marker does not have to index the instrument.
Makhuwa (ISO 639-3: vmw, Glottolog: makh1264)
Makhuwa has an instrumental applicative marker él'. The same form also functions as benefactive and locative/directive applicative. Makhuwa is coded 1.
Amíná o-n-rúw-él' eshimá nkhóri 1.Amina 1-PRS.CJ-stir-APPL 9.shima 3.spoon ‘Amina prepares shima with a spoon.’ (van der Wal 2009: 72)
Haspelmath, Martin & Thomas Müller-Bardey. 2004. Valency change. In Geert E. Booij, Christian Lehmann, Joachim Mugdan & Stavros Skopeteas (eds), Morphology: An international handbook on inflection and word-formation. Vol. 2, 1130–1145. Berlin: Walter de Gruyter.
Peterson, David A. 2007. Applicative constructions. Oxford: Oxford University Press.
Polinsky, Maria. 2013. Applicative constructions. In Matthew S. Dryer & Martin Haspelmath (eds), The world atlas of language structures online. Leipzig: Max Planck Institute for Evolutionary Anthropology.
Stolz, Thomas. 1996. Some instruments are really good companions – some are not. On syncretism and the typology of instrumentals and comitatives. Theoretical Linguistics 23. 113–200.
Stolz, Thomas. 2001. To be with X is to have X: Comitatives, instrumentals, locative, and predicative possession. Linguistics 39. 321–350.
Stolz, Thomas. 2001. Comitatives vs. instrumentals vs. agents. In Walter Bisang (ed.), Aspects of typology and universals, 153–174. Berlin: Akademie Verlag.
Zúñiga, Fernando & Seppo Kittilä. 2019. Grammatical voice. (Cambridge Textbooks in Linguistics, 59.) Cambridge: Cambridge University Press.
van der Wal, Jenneke. 2009. Word order and information structure in Makhuwa-Enahara. Leiden: Leiden University. (Doctoral dissertation.)