Semitic languages exhibit rich nonconcatenative morphological operations, which can generate a myriad of derived lexemes. Especially, the feature rich, root-driven morphology in the Arabic language demonstrates the construction of several verb-derived nominals (verbal nouns) such as gerunds, active participles, passive participles, locative participles, etc. Although HPSG is a successful syntactic theory, it lacks the representation of complex nonconcatenative morphology. In this paper, we propose a novel HPSG representation for Arabic nominals and various verb-derived nouns. We also present the lexical type hierarchy and derivational rules for generating these verb-derived nominals using the HPSG framework.

Arabic language is very rich in grammatical declen sion of nouns and verbs. In classical Arabic, there are Ive classes of verb lexemes and these are declined in four ways. Modeling the morphological effect of such a rich declension system is a challenging problem and is essential for processing of Arabic language. In this paper, we use Head-Driven Phase Structure Grammar GIPSG) to analyze the declension system of Arabic verbs based on lexical types. We design lexical type hierarchy of Arabic verbs and show the mapping of lexical type to declension type from this type hierarchy. We also design construction rules to capture the morphological and syntactic effect of declension types dynamically. Finally, we have implemented the lexical type hierarchy and construction rules in the TRALE platform to validate the proposed formalism. This work effectively extends the capabilities of existing HPSG framework for supporting declension of verbs in Arabic.