Abstract
Authoring OWL ontologies is hard for both domain experts and ontology engineers unless they have good knowledge of mathematics and logic. Thus, controlled natural languages (CNLs) have been proposed for easier authoring of ontologies via statements that can be automatically translated to OWL. Unfortunately, most of these languages are controlled English languages. Though they typically allow using non-English identifiers for representing concepts, instances (of concepts), and relationships, keywords remain English. This makes statements awkward and both hard and slow to read and write. Besides, error messages are generated in English only. Thus, this paper proposes the first controlled Arabic language (CAL) for authoring ontologies using Arabic words only. CAL is accompanied by a tool to allow translating CAL statements to OWL. Detailed error messages are also generated in Arabic. Besides, CAL is based on and has a similar syntax as the controlled English language Rabbit, and thus, statements can be easily translated between both languages allowing the cooperation of Arabic-speaking and English-speaking domain experts and ontology engineers in ontology authoring and validation, a capability which is absent in other CNLs. The advantages of CAL have been empirically tested to support our claim regarding the need to develop a controlled language corresponding to each natural language other than English. Nevertheless, an additional layer, NCAL, allows developing ontologies in a more-natural CAL in comparison with CAL. Many linguistic challenges and specific features of the Arabic language have been considered when designing both CAL and NCAL.