A method and apparatus for recognizing the topic structure of language. Language data is divided into simple sentences and a prominent noun portion (PNP) extracted from each. The simple sentences are divided into blocks of data dealing with a single subject. A starting point of at least one topic is detected and a topic introducing region of each topic is determined from block information and language data characteristics. A PNP satisfying a predetermined condition is chosen from the PNPs in each determined topic intro. region as the topic portion (TP) of the topic in the topic intro. region. A topic level indicating a depth of nesting of each topic and a topic scope indicating a region over which the topic continues is determined from the TP and sentences before and after the TP. Sub-topic intro. regions in the remaining area where no topic intro. regions are recognized are determined from block information and language data characteristics. A PNP satisfying a predetermined condition is chosen from the PNPs in each determined sub-topic intro. region as the sub-topic portion (STP) of the sub-topic in the sub-topic intro. region. A temporary topic level indicating a depth of nesting of each sub-topic and a sub-topic scope indicating a region over which the sub-topic continues is determined from the STP and sentences before and after the STP. All determined topics and sub-topics are unified by revising the temporary topic level of each sub-topic according to the topic level of each topic. These topics and their levels are output as a topic structure.
Method and apparatus for recognizing topic structure of language data