Building a general speech interface independent of Intelligent Performance Systems (IPS) is an important technique for efficient construction of spoken dialog systems. This paper describes dialog management for speech output in MASCOTS-II which is a dialog manager in such an interface system. MASCOTS-II carries out dialog management based on two mechanisms; SR-plan analyzes the dialog structure of utterances and TPN (Topic Packet Network) models the topic transition in dialog. In speech output of this framework, output messages from IPS are described with concept representation which is based on the case structure and the phrase patterns. MASCOTS-II receives concept representation from IPS and modifies it according to the dialog context. Modified concept representation is converted into synthetic speech by SOCS, a concept-to-speech conversion system in the interface. MAS-COTS-II extracts emphatic words to add prominence so that the user pays his/her attention to important information in the IPS utterance. It also has a mechanism for restoring missing words in IPS utterance to notify the recognition result to the user. The concept representation is rewritten in terms of phrase pattern named custom template, if it is possible.