Abstract: Computer method and apparatus for segmenting text streams is disclosed. Given is an input text stream formed of a series of words. A probability member provides working probabilities that a group of words is of a topic selected from a plurality of predetermined topics. The probability member accounts for relationships between words. A processing module receives the input text stream and using the probability member determines probability of certain words in the input text stream being of a same topic. As such, the processing module segments the input text stream into single topic groupings of words, where each grouping is of a respective single topic.