A SUI has many consumers and must simultaneously satisfy many objectives. Among the consumers of SUIs are marketers, service providers, end users, and developers.
Marketers have the responsibility of selling speech applications to service providers. The primary objective of a SUI from a marketer's point of view is to appeal to the targeted service provider, thus helping to make the sale.
Service providers rely on the speech application to help them provide a service to end users. For service providers, the primary objectives of an SUI are to save money and maintain customer contact and satisfaction. To this end, they are also concerned with their corporate image and how their speech applications will fit into their overall branding strategies.
End users call the speech application for the purpose of obtaining a service from the service provider. End users want SUIs that are easy to use, allow efficient task completion, and provide a pleasant user experience.
Developers must write the code that creates the entire speech application, including the SUI. The primary objectives for developers creating SUIs are that the interface be technologically feasible, capable of completion given resource constraints, and require minimal development effort.