13. The information processing apparatus of claim 11 , wherein the CPU is further configured to: select the keyword from the first morpheme subset; determine, based on the contextual information, a keyword meaning associated with the keyword; and compute a frequency at which the keyword occurs within the text data.
13. The information processing apparatus of claim 11 , wherein the CPU is further configured to: select the keyword from the first morpheme subset; determine, based on the contextual information, a keyword meaning associated with the keyword; and compute a frequency at which the keyword occurs within the text data. 16. The information processing apparatus of claim 13 , wherein the CPU is further configured to generate tag information associated with the text data, the tag information comprising the keyword and the keyword meaning.