Abstract
The need to make the contents of the Semantic Web accessible to end-users becomes increasingly pressing as
the amount of information stored in ontology-based knowledge bases steadily increases. Natural language interfaces
(NLIs) provide a familiar and convenient means of query access to Semantic Web data for casual end-users. While
several studies have shown that NLIs can achieve high retrieval performance as well as domain independence, this
paper focuses on usability and investigates if NLIs and natural language query languages are useful from an enduser’s
point of view. To that end, we introduce four interfaces each allowing a different query language and present
a usability study benchmarking these interfaces. The results of the study reveal a clear preference for full natural
language query sentences with a limited set of sentence beginnings over keywords or formal query languages. NLIs
to ontology-based knowledge bases can, therefore, be considered to be useful for casual or occasional end-users. As
such, the overarching contribution is one step towards the theoretical vision of the Semantic Web becoming reality.
Kaufmann, E