A topic segmenting system segments a topic into chatter and subtopics. The system decomposes a conversation into topics, producing a time-based structure for topics and subtopics in the conversation. The system extracts a large number of topics at all levels of granularity. Some of the topics extracted correspond to broad topics and some correspond to "spiky" topics or subtopics. The system comprises a process for automatically detecting spiky regions of a topic. For each possible broad topic, the present system finds regions where coverage of the broad topic overlaps significantly with the spiky region of another topic. The system then removes the spiky subtopic from the conversation. Processing is repeated until all discernable topics have been identified and removed from the conversation, yielding random topics of little duration or intensity.