To design complicated language services for intercultural collaboration, it is important to consider how to compose different atomic language services so as to satisfy the requirements raised by the users. In the research area of services computing, many approaches to QoS-aware service composition have been proposed, where the assumption is that the QoS of a composite service can be calculated by aggregating the individual QoS values of atomic services. However, the QoS of a composite service is difficult to predict due to the QoS uncertainty of services in the real world. In this chapter, we address the above concerns by proposing a service design approach based on user-centered QoS and then confirming it in a case study of language service design for multi-language communication. To achieve this goal, we first introduce a QoS model to address the issues of user requirements and QoS uncertainty. We then propose a service design process that consists of composite service generation, participatory simulation, QoS evaluation and QoS data update. Finally, we introduce a field study of multi-language service design for agricultural knowledge communication to elucidate the benefits of our proposal approach.