Morphological Segmentation and Part-of-Speech Tagging for the Arabic Heritage

We annotate 60,000 words of Classical Arabic (CA) with topics in philosophy, religion, literature, and law with fine-grain segment-based morphological descriptions. We use these annotations for building a morphological segmenter and part-of-speech (POS) tagger for CA. With character-level classification and features from the word and its lexical context, the segmenter achieves a word accuracy of 96.8% with the main issue being a high rate of out-of-vocabulary words. A token-based POS tagger achieves an accuracy of 96.22% with 97.72% on known tokens despite the small size of the corpus. An error analysis shows that most of the tagging errors are results of segmentation and that quality improves with more data being added. The morphological segmenter and tagger have a wide range of potential applications in processing CA, a low-resource variety of the language.