Current Spoken Language Understanding systems rely either on hand-written semantic grammars or on flat attribute-value sequence labeling. In both approaches, concepts and their relations (when modeled at all) are domain-specific, thus making it difficult to expand, port or share the domain model.

To address this issue, we introduce: 1) a domain model based on an ontology where concepts are classified into either as predicate or argument; 2) the modeling of relations between such concept classes in terms of classical relations as defined in lexical semantics. We study and analyze our approach on the spoken dialog corpus collected within a problem-solving task in the LUNA project. We evaluate the coverage and relevance of the ontology for the interpretation of spoken utterances.