Word Segmentation of Informal Arabic with Domain Adaptation

Segmentation of clitics has been shown to improve accuracy on a variety of Arabic NLP tasks. However, state-of-the-art Arabic word segmenters are either limited to formal Modern Standard Arabic, performing poorly on Arabic text featuring dialectal vocabulary and grammar, or rely on linguistic knowledge that is hand-tuned for each dialect. We extend an existing MSA segmenter with a simple domain adaptation technique and new features in order to segment informal and dialectal Arabic text. Experiments show that our system outperforms existing systems on newswire, broadcast news and Egyptian dialect, improving segmentation F-1 score on a recently released Egyptian Arabic corpus to 95.1%, compared to 90.8% for another segmenter designed specifically for Egyptian Arabic.