A system (and method) for off-line detection of textual topical changes includes at least one central processing unit (CPU), at least one memory coupled to the at least one CPU, a network connectable to the at least one CPU, and a database, stored on the at least one memory, containing a plurality of textual data set of topics. The CPU executes first and second processes in first and second directions, respectively, for extracting a segment having a predetermined size from a text, computing likelihood scores of a text in the segment for each topic, computing likelihood ratios, comparing them to a threshold, and defining whether there is a change point at the current last word in a window.