Question answering systems: the story till the Arabic linked data

Question answering system (QAS) is essential to satisfy the need to query information available in various formats, including structured data (ontology, databases) or unstructured data (document, web). The QAS provides a correct response to the question asked by a user in natural language. QAS uses natural language processing (NLP) techniques to interface with the system user. In this paper, we survey various QAS such as Natural Language Interfacing to DataBases (NLIDB), ontology-based question answering and question answering systems for unstructured data. We give also statistics and analysis. This can help researchers to choose an appropriate solution to their issues. In case of insufficiency, they can propose new systems for complex queries and adapt or reuse QAS techniques for specific research issues. We give also our point of view on how can QAS deal with Arabic linked data.