The main metadata projects for linguistic (language) resources developed over the past 20 years are described. These include the IMDI initiative, the OLAC metadata system. the META-SHARE meta-model, the International Standard Number of Language resources, the evaluation map of language resources, and the CLARIN component metadata model. The content of the ISO metadata standard is described. Projects for creating dictionaries, ontologies, and lexical databases for metadata of language resources are described.