Since various communities, which use multiple languages, now want to interact in daily life, tools that can effectively support multilingual communication are necessary. However, we often observe that the success of a multilingual tool in one situation does not guarantee its success in another. To develop a multilingual environment that can handle various situations in various communities, existing language resources (dictionaries, parallel texts, part-of-speech taggers, machine translators, etc.) should be easily shared and customized. Therefore, we designed our proposal, the Language Grid, as service-oriented collective intelligence; it allows users to freely create language services from existing language resources and combine those language services to develop new services to meet their own requirements. This chapter explains the design concept and service architecture of the Language Grid, and the approach of user involvement in the collective intelligence activities.