The existing platforms designed to ensure interoperability of language services define their own data format and annotation vocabularies. To construct a comprehensive language service infrastructure, various types of language services supporting different languages need to be connected to the platforms. However, it is difficult for a single operator to collect and organize services for two key reasons: what kinds of language services are registered depends on the purpose of the platforms, and the language resources are characterized by their locality. Therefore, federation of the platforms across regions is essential to establish the comprehensive infrastructure desired. In this chapter, we extend the existing service grid architecture to federate heterogeneous as well as homogeneous language service platforms. To this end, we introduce an upper-level ontology for a service grid that facilitates the semantic integration of domain ontologies and guides the development of new domain ontologies. Moreover, we also introduce a federated grid architecture that can share language service registries, and compose language services across service grids.