---
title: "Ambiguity in Explicit Discourse Connectives — Webber 2019"
description: "The paper argues that explicit discourse connectives can be ambiguous in more ways than usually assumed."
authors: ["Bonnie Webber", "Rashmi Prasad", "Alan Lee"]
year: 2019
venue: "Proceedings of the 13th International Conference on Computational Semantics - Long Papers"
source: "https://aclanthology.org/W19-0411/"
doi: "10.18653/v1/w19-0411"
licence: "CC BY 4.0 (ACL Anthology)"
licence_url: "https://creativecommons.org/licenses/by/4.0/"
summary_licence: "Elamur Cosmic License"
canonical: "https://research.elamur.ai/free/papers/webber-2019-ambiguity-explicit-discourse-connectives/"
---
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# Ambiguity in Explicit Discourse Connectives

**Authors:** [Bonnie Webber](https://md.research.elamur.ai/free/authors/bonnie-webber/), [Rashmi Prasad](https://md.research.elamur.ai/free/authors/rashmi-prasad/), [Alan Lee](https://md.research.elamur.ai/free/authors/alan-lee/) · **Year:** 2019 · **Venue:** Proceedings of the 13th International Conference on Computational Semantics - Long Papers · **Licence:** [CC BY 4.0 (ACL Anthology)](https://creativecommons.org/licenses/by/4.0/)

**Links:** [Publisher's page](https://aclanthology.org/W19-0411/) · [PDF](https://aclanthology.org/W19-0411.pdf) · [DOI 10.18653/v1/w19-0411](https://doi.org/10.18653/v1/w19-0411) · [OpenAlex](https://openalex.org/W2954982705)

**Citations:** 10 citations (openalex-snapshot · 2026-10-14) · [6](#cited-by) in our library, of the 140673 papers whose bibliographies we read

## Summary
The paper argues that explicit discourse connectives can be ambiguous in more ways than usually assumed. Earlier work, notably Pitler and Nenkova (2009), addressed two kinds: whether a token acts as a connective at all (usage) and which relation it signals (sense). The authors survey four further ambiguity types that are well known for other linguistic forms, using examples and counts from the newly released PDTB-3.

The four types are:
- **Part-of-speech:** the same word acting as a conjunction or an adverbial.
- **Multi-word expression:** a string read as separate words or as one connective.
- **Scope:** an ambiguity that changes the relation's sense.
- **Semantic role:** which argument of a CONCESSION relation cancels the expected inference.

They also show that the expanded PDTB-3 sense hierarchy creates new sense ambiguities that were absent in the PDTB-2.

The paper is a position and analysis study rather than a new model. Its point is that overlooking these ambiguities causes mislabelled relations, both in manual annotation and in automatic shallow discourse parsing. It calls on researchers to test whether syntax-based disambiguation is sufficient or needs extending.

## Key points
- **Corpus sizes:** The PDTB-2 has over 43K relations, about 18.4K of them explicit. The PDTB-3 adds roughly 12.5K intra-sentential and 1K inter-sentential relations. Of its ~53,600 tokens, about 57% are unchanged from the PDTB-2, 19% were revised, and 24% are new.
- **New sense, new ambiguity:** COMPARISON.SIMILARITY was applied to 135 new tokens and 68 re-annotated ones (41 explicit). This makes connectives such as *as well*, *as if* and *while* newly ambiguous, whereas *similarly* remains unambiguous.
- **Part-of-speech ambiguity:** *since*, *before* and *however* change their sense, sometimes to the reverse temporal or concessive direction, depending on PoS (IN vs. RB, or RB vs. WRB). Correct PoS tagging is enough to resolve this.
- **Multi-word and scope ambiguity:** Examples of the multi-word type are *only to*, *but also*, *but then* and *or otherwise*. For scope, about 9% of over 1,600 relations with a to-clause Arg2 were labelled CONDITION.ARG2-AS-COND, and syntax alone may not resolve such cases.
- **Semantic role ambiguity:** This affects postposed *although*, *though*, *even though* and *while*. Of 324 PDTB-3 tokens, 260 are ARG1-AS-DENIER and 64 are ARG2-AS-DENIER. The 402 preposed tokens are treated as unambiguous.

*Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.*

Fields: [Linguistics & languages](https://md.research.elamur.ai/free/shelves/linguistics/)

Topics: [Discourse analysis](https://md.research.elamur.ai/free/topics/discourse-analysis/) · [Part-of-speech tagging](https://md.research.elamur.ai/free/topics/part-of-speech-tagging/)

## Cited by

Cited by

6 papers of our library cite it (of the 140673 whose bibliographies we read); 3 of them have a page here, 3 not yet.

- [Contextualized Embeddings for Connective Disambiguation in Shallow Discourse Parsing](https://md.research.elamur.ai/free/papers/knaebel-2020-contextualized-embeddings-connective-disambiguation-shallow/)
- [What Causes the Failure of Explicit to Implicit Discourse Relation Recognition?](https://md.research.elamur.ai/free/papers/liu-2024-what-causes-failure-explicit-implicit/)
- [Pragmatic competence of pre-trained language models through the lens of discourse connectives](https://md.research.elamur.ai/free/papers/pandia-2021-pragmatic-competence-pre-trained-language/)

## Cite

The paper itself, not this page. BibTeX from the library's record of the work.

```bibtex
@inproceedings{webber2019ambiguity,
  title = {{Ambiguity in Explicit Discourse Connectives}},
  author = {Webber, Bonnie and Prasad, Rashmi and Lee, Alan},
  booktitle = {Proceedings of the 13th International Conference on Computational Semantics - Long Papers},
  year = {2019},
  doi = {10.18653/v1/w19-0411},
  url = {https://doi.org/10.18653/v1/w19-0411}
}
```

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## References

10 references, 5 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet.

1. Hollenstein, N., N. Schneider, and B. Webber (2016). Inconsistency detection in semantic annotation. In Proceedings, Language Resources and Evaluation Conference (LREC 2016), Potoroz, Slovenia. [find](https://scholar.google.com/scholar?q=Hollenstein%2C+N%2E%2C+N%2E+Schneider%2C+and+B%2E+Webber+%282016%29%2E+Inconsistency+detection+in+semantic+annotation%2E+In+Proceedings%2C+Language+Resources+and+Evaluation+Conference+%28LREC+2016%29%2C+Potoroz%2C+Slovenia%2E)
2. Konstas, I., F. Keller, V. Demberg, and M. Lapata (2014). Incremental semantic role labeling with tree adjoining grammar. In Proceedings, Empirical Methods in Natural Language Processing. [find](https://scholar.google.com/scholar?q=Konstas%2C+I%2E%2C+F%2E+Keller%2C+V%2E+Demberg%2C+and+M%2E+Lapata+%282014%29%2E+Incremental+semantic+role+labeling+with+tree+adjoining+grammar%2E+In+Proceedings%2C+Empirical+Methods+in+Natural+Language+Processing%2E)
3. Pitler, E. and A. Nenkova (2009). Using syntax to disambiguate explicit discourse connectives in text. In ACL-IJCNLP ’09: Proceedings of the 47th Meeting of the Association for Computational Linguistics and the 4th International Joint Conference on Natural Language Processing. [find](https://scholar.google.com/scholar?q=Pitler%2C+E%2E+and+A%2E+Nenkova+%282009%29%2E+Using+syntax+to+disambiguate+explicit+discourse+connectives+in+text%2E+In+ACL%2DIJCNLP+%E2%80%9909%3A+Proceedings+of+the+47th+Meeting+of+the+Association+for+Computational+Linguisti) [our card](https://md.research.elamur.ai/free/papers/pitler-2009-syntax-disambiguate-explicit-discourse-connectives/)
4. Prasad, R., N. Dinesh, A. Lee, E. Miltsakaki, L. Robaldo, A. Joshi, and B. Webber (2008). The Penn Discourse TreeBank 2.0. In Proceedings, 6th International Conference on Language Resources and Evaluation, Marrakech, Morocco. [find](https://scholar.google.com/scholar?q=Prasad%2C+R%2E%2C+N%2E+Dinesh%2C+A%2E+Lee%2C+E%2E+Miltsakaki%2C+L%2E+Robaldo%2C+A%2E+Joshi%2C+and+B%2E+Webber+%282008%29%2E+The+Penn+Discourse+TreeBank+2%2E0%2E+In+Proceedings%2C+6th+International+Conference+on+Language+Resources+and+Evalua) [our card](https://md.research.elamur.ai/free/papers/disc-2008-prasad-penn-discourse-treebank-2-0/)
5. Prasad, R., B. Webber, and A. Joshi (2014). Reflections on the Penn Discourse Treebank, comparable corpora and complementary annotation. Computational Linguistics 40(4), 921–950. [find](https://scholar.google.com/scholar?q=Prasad%2C+R%2E%2C+B%2E+Webber%2C+and+A%2E+Joshi+%282014%29%2E+Reflections+on+the+Penn+Discourse+Treebank%2C+comparable+corpora+and+complementary+annotation%2E+Computational+Linguistics+40%284%29%2C+921%E2%80%93950%2E) [our card](https://md.research.elamur.ai/free/papers/prasad-2014-reflections-penn-discourse-treebank-comparable/)
6. The PDTB Research Group (2008). The Penn Discourse TreeBank 2.0 Annotation Manual. Available at [http://www.seas.upenn.edu/˜pdtb/](http://www.seas.upenn.edu/˜pdtb/), or as part of the download of LDC2008T05. [↗](http://www.seas.upenn.edu/˜pdtb/)
7. Webber, B., R. Prasad, A. Lee, and A. Joshi (2019). The Penn Discourse Treebank 3.0 Annotation Manual. Technical report, University of Pennsylvania. Available at [https://catalog.ldc.upenn.edu/docs/LDC2019T05/PDTB3-Annotation-Manual.pdf](https://catalog.ldc.upenn.edu/docs/LDC2019T05/PDTB3-Annotation-Manual.pdf). [↗](https://catalog.ldc.upenn.edu/docs/LDC2019T05/PDTB3-Annotation-Manual.pdf)
8. Xue, N., H. T. Ng, S. Pradhan, R. Prasad, C. Bryant, and A. Rutherford (2015). The CoNLL-2015 shared task on shallow discourse parsing. In Proc 19 th Conference on Computational Natural Language Learning – Shared Task, Beijing, pp. 1–16. [find](https://scholar.google.com/scholar?q=Xue%2C+N%2E%2C+H%2E+T%2E+Ng%2C+S%2E+Pradhan%2C+R%2E+Prasad%2C+C%2E+Bryant%2C+and+A%2E+Rutherford+%282015%29%2E+The+CoNLL%2D2015+shared+task+on+shallow+discourse+parsing%2E+In+Proc+19+th+Conference+on+Computational+Natural+Language+Learn) [our card](https://md.research.elamur.ai/free/papers/xue-2015-conll-2015-shared-task-shallow/)
9. Xue, N., H. T. Ng, S. Pradhan, A. Rutherford, B. Webber, C. Wang, and H. Wang (2016). [find](https://scholar.google.com/scholar?q=Xue%2C+N%2E%2C+H%2E+T%2E+Ng%2C+S%2E+Pradhan%2C+A%2E+Rutherford%2C+B%2E+Webber%2C+C%2E+Wang%2C+and+H%2E+Wang+%282016%29%2E)
10. CoNLL 2016 shared task on multilingual shallow discourse parsing. In Proc 20 th Conference on Computational Natural Language Learning – Shared Task, Berlin, pp. 1–19. [find](https://scholar.google.com/scholar?q=CoNLL+2016+shared+task+on+multilingual+shallow+discourse+parsing%2E+In+Proc+20+th+Conference+on+Computational+Natural+Language+Learning+%E2%80%93+Shared+Task%2C+Berlin%2C+pp%2E+1%E2%80%9319%2E) [our card](https://md.research.elamur.ai/free/papers/xue-2016-conll-2016-shared-task-multilingual/)
