1. A method for sentence planning in a task classification system that interacts with a user, comprising: recognizing symbols in the user's input communication; determining whether the user's input communication can be understood, wherein if the user's communication can be understood, understanding data is generated; generating communicative goals based on the recognized symbols and understanding data, the generated communicative goals being related to information needed to be obtained from the user; automatically planning one or more sentences based on the generated communicative goals; and outputting at least one of the one or more sentences plans to the user.