Ontology, part-whole relations, isiZulu and culture

The title is a mouthful, but it can go together. What’s interesting, is that the ‘common’ list of part-whole relations are not exactly like that in isiZulu and Zulu culture.

Part-whole relations have been proposed over the past 30 years, such as to relate a human heart to the human it is part of, that Gauteng is located in South Africa (geographically a part of), and the slice of the cake is a portion of the cake, and they seemed well-established by now. The figure below provides an informal view of it.

Informal taxonomy of common part-whole relations (source: [2])

My co-author, Langa Khumalo, and I already had an inkling this hierarchy probably would not work for isiZulu, based, first, on a linguistic analysis to generate natural language [1], and, second, the Shuter & Shooter English-isiZulu dictionary already lists 18 translations for just ‘part’ alone. Yet, if those ‘common’ part-whole relations are universal, the differences observed ought to be just an artefact of language, not ontological differences. To clear up the matter, we guided ourselves with the following questions:

  1. Which part-whole relations have been named in isiZulu, and to what extent are they not only lexically but also semantically distinct?
  2. Can all those part-whole relations be mapped with equivalence relations to the common part-whole relations?
  3. For those that cannot be mapped with equivalence relations: is the difference in meaning ontologically possibly interesting for ontology engineering?
  4. Is there something different as gleaned from isiZulu part-whole relations that is useful in improving the theoretical appreciation of part-whole relations?

To figure this out, we first took a bottom-up approach with evidence gathering, and then augmented it with further ontological analysis. Plodding though the isiZulu-English dictionaries got us 81 terms that had something to do with parts. 41 were discarded because they were not applicable upon closer inspection (e.g., referring to creating parts cf. relating parts, idioms). Further annotations and examples were added, which reduced it to 28 (+ 3 we had missed and were added). Of those 28, we selected 13 for ontological analysis and formalisation. That selection was based on importance (like ingxenye) and some of them that seemed a bit overly specific, like iqatha for portions of meat, and meat only. The hierarchy of the final selection is shown in the figure below, with an informal indication of what the relation relates.

Selected isiZulu terms with informal descriptions. (Source: [2])

They held up ontologically, i.e., some are the same as the ‘common’ ones, yet some others are really different, like the hlanganyela for a collective (cf. individual object) being part of (participating in) an event. Admitted, some of the domains/ranges aren’t very clearly delineated. For instance, isiqephu relates solid and ‘solid-like’ portions, as in, e.g., Zonke izicezu zesinkwa ziyisiqephu sesinkwa esisodwa ‘all slices of bread are a portion of some loaf of bread’. Where exactly that border of ‘solid-like’ is and when it really counts as a liquid (and thus isiqephu applies no more), is not yet clear—that’s a separate question orthogonal to the relation. Nonetheless, the investigation did clear up several things, especially the more precise umunxa that took me a while to unravel, which turned out to be a chain of parthood relations; e.g., the area where the fireplace is in the hut is a portion of the hut (sample use with the verbaliser: Onke amaziko angumunxa wexhiba). We didn’t touch upon really thorny issues that probably will deserve a paper of their own. For instance, the temporalised parthood isihlephu is used to relate a meaningful scattered part with identity to the whole it was part of, such as the broken-off ear of a cup that was part of the cup (but it cannot be used for the chip of the cup, as a chip isn’t identifiable in the same way as the ear is).

We did try to test the terms against the isiZulu National Corpus to see how the terms are used, but with the limited functionalities and tooling, not as much came out of it as we had hoped for. In any case, the detailed assessment of a section of the corpus did show the relevant uses were not contradicting the formalisation.

Further details can be found in our paper “On the ontology of part-whole relations in Zulu language and culture” that will be presented at the 10th International Conference on Formal Ontology in Information Systems 2018 (FOIS’18) that will be held from 17 to 21 September in Cape Town, South Africa.

As far as I know, this is the first such investigation. Checking out other languages a bit (mainly Spanish and German), and some related works on Turkish and Chinese, it might be the case that also there the ‘common’ part-whole relations may not be exactly the same. We carried out whole process systematically, which is described as such in the paper, so that anyone who’d like to do something like this for another language region and culture, could follow the same procedure.



[1] Keet, C.M., Khumalo, L. On the verbalization patterns of part-whole relations in isiZulu. 9th International Natural Language Generation conference (INLG’16), September 5-8, 2016, Edinburgh, UK. ACL, 174-183.

[2] Keet, C.M., Khumalo, L. On the ontology of part-whole relations in Zulu language and culture. 10th International Conference on Formal Ontology in Information Systems 2018 (FOIS’18). IOS Press. 17-21 September, 2018, Cape Town, South Africa. (in print)


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