Abstract
Brazilian Portuguese (BP) and European Portuguese (EP) have specific NLP resources and tools for many tasks. It is generally agreed upon that applying them to the variant other than their intended one results in a performance drop; however, very little research has measured it. We evaluated a POS tagger in a cross-variant setting under multiple combinations of word embeddings, train and test corpora, and found that (i) BP is easier than EP, (ii) word embeddings help increase tagger performance significantly, but not enough to close the accuracy gap in a cross-variant setting and (iii) embeddings generated from a corpus with both variants are useful in cross-variant scenarios. While we cannot generalize observations from POS tagging to any NLP task, this is an important first step for such evaluations.
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Notes
- 1.
The texts explored here are from before the Spelling Agreement of the Portuguese language taking place.
- 2.
More information about the workshops on http://ttg.uni-saarland.de/lt4vardial2015/.
- 3.
Many of these OOV words are common in both variants, but since the Bosque corpus is very small, they only appear in one of the halves.
- 4.
Available at http://www.linguateca.pt/cetempublico/.
- 5.
The Bosque corpus is composed of sentences from CETENFolha and CETEMPúblico. We removed all those sentences to avoid any overlap with the labeled corpus.
- 6.
Remember that their BP and EP corpora are not the same as ours.
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This work was funded by grant#2013/22973-0 of the São Paulo Research Funding Agency (FAPESP).
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Fonseca, E.R., Aluísio, S.M. (2016). Improving POS Tagging Across Portuguese Variants with Word Embeddings. In: Silva, J., Ribeiro, R., Quaresma, P., Adami, A., Branco, A. (eds) Computational Processing of the Portuguese Language. PROPOR 2016. Lecture Notes in Computer Science(), vol 9727. Springer, Cham. https://doi.org/10.1007/978-3-319-41552-9_22
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