Rights statement: © ACM, 2019. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in ACM Transactions on Asian and Low-Resource Language Information Processing, 18, 4, 2019 http://doi.acm.org/10.1145/3314942
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Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Article number | 42 |
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<mark>Journal publication date</mark> | 31/08/2019 |
<mark>Journal</mark> | ACM Transactions on Asian and Low-Resource Language Information Processing (TALLIP) |
Issue number | 4 |
Volume | 18 |
Number of pages | 26 |
Publication Status | Published |
Early online date | 21/05/19 |
<mark>Original language</mark> | English |
Part-of-speech (POS) tagging is a well-established technology for most Western European languages and a few other world languages, but it has not been evaluated on Igbo, an agglutinative African language. This article presents POS tagging experiments conducted using an Igbo corpus as a test bed for identifying the POS taggers and the Machine Learning (ML) methods that can achieve a good performance with the small dataset available for the language. Experiments have been conducted using different well-known POS taggers developed for English or European languages, and different training data styles and sizes. Igbo has a number of language-specific characteristics that present a challenge for effective POS tagging. One interesting case is the wide use of verbs (and nominalizations thereof) that have an inherent noun complement, which form “linked pairs” in the POS tagging scheme, but which may appear discontinuously. Another issue is Igbo's highly productive agglutinative morphology, which can produce many variant word forms from a given root. This productivity is a key cause of the out-of-vocabulary (OOV) words observed during Igbo tagging. We report results of experiments on a promising direction for improving tagging performance on such morphologically-inflected OOV words.