Ontology languages are specialized languages used to define and represent knowledge in a structured way. They allow for the creation of formal models that describe the relationships between different concepts within a specific domain. Common ontology languages include OWL (Web Ontology Language) and RDF (Resource Description Framework), which help in sharing and reusing knowledge across different systems. These languages enable machines to understand and process information more effectively, facilitating tasks like data integration and semantic search. By providing a common framework, ontology languages support interoperability among diverse applications, making it easier to manage complex information and enhance communication between systems.