Salam Khalifa


2020

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Morphological Analysis and Disambiguation for Gulf Arabic : The Interplay between Resources and MethodsGulf Arabic: The Interplay between Resources and Methods
Salam Khalifa | Nasser Zalmout | Nizar Habash
Proceedings of the 12th Language Resources and Evaluation Conference

In this paper we present the first full morphological analysis and disambiguation system for Gulf Arabic. We use an existing state-of-the-art morphological disambiguation system to investigate the effects of different data sizes and different combinations of morphological analyzers for Modern Standard Arabic, Egyptian Arabic, and Gulf Arabic. We find that in very low settings, morphological analyzers help boost the performance of the full morphological disambiguation task. However, as the size of resources increase, the value of the morphological analyzers decreases.

2019

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A Little Linguistics Goes a Long Way : Unsupervised Segmentation with Limited Language Specific Guidance
Alexander Erdmann | Salam Khalifa | Mai Oudah | Nizar Habash | Houda Bouamor
Proceedings of the 16th Workshop on Computational Research in Phonetics, Phonology, and Morphology

We present de-lexical segmentation, a linguistically motivated alternative to greedy or other unsupervised methods, requiring only minimal language specific input. Our technique involves creating a small grammar of closed-class affixes which can be written in a few hours. The grammar over generates analyses for word forms attested in a raw corpus which are disambiguated based on features of the linguistic base proposed for each form. Extending the grammar to cover orthographic, morpho-syntactic or lexical variation is simple, making it an ideal solution for challenging corpora with noisy, dialect-inconsistent, or otherwise non-standard content. In two evaluations, we consistently outperform competitive unsupervised baselines and approach the performance of state-of-the-art supervised models trained on large amounts of data, providing evidence for the value of linguistic input during preprocessing.

2018

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An Arabic Morphological Analyzer and Generator with Copious FeaturesArabic Morphological Analyzer and Generator with Copious Features
Dima Taji | Salam Khalifa | Ossama Obeid | Fadhl Eryani | Nizar Habash
Proceedings of the Fifteenth Workshop on Computational Research in Phonetics, Phonology, and Morphology

We introduce CALIMA-Star, a very rich Arabic morphological analyzer and generator that provides functional and form-based morphological features as well as built-in tokenization, phonological representation, lexical rationality and much more. This tool includes a fast engine that can be easily integrated into other systems, as well as an easy-to-use API and a web interface. CALIMA-Star also supports morphological reinflection. We evaluate CALIMA-Star against four commonly used analyzers for Arabic in terms of speed and morphological content.

2017

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A Morphological Analyzer for Gulf Arabic VerbsGulf Arabic Verbs
Salam Khalifa | Sara Hassan | Nizar Habash
Proceedings of the Third Arabic Natural Language Processing Workshop

We present CALIMAGLF, a Gulf Arabic morphological analyzer currently covering over 2,600 verbal lemmas. We describe in detail the process of building the analyzer starting from phonetic dictionary entries to fully inflected orthographic paradigms and associated lexicon and orthographic variants. We evaluate the coverage of CALIMA-GLF against Modern Standard Arabic and Egyptian Arabic analyzers on part of a Gulf Arabic novel. CALIMA-GLF verb analysis token recall for identifying correct POS tag outperforms both the Modern Standard Arabic and Egyptian Arabic analyzers by over 27.4 % and 16.9 % absolute, respectively.