1. An information processing apparatus comprising: input means for inputting non-linguistic information including a user's vital sign information and for inputting linguistic information, wherein the user's vital sign information includes at least one of a pulse, a blood flow, a blood pressure, breathing, body temperature, skin surface temperature, electric resistance of skin, sweat, brain waves, and brain magnetism and wherein the linguistic information includes recorded linguistic information; an extractor means for extracting emotional linguistic information from said recorded linguistic information by identifying in the recorded linguistic information first keywords representative of emotional states and second keywords representative of a strength level of the identified first keywords; learning means for learning an emotion of the user by relating the non-linguistic information to said emotional linguistic information; storage means for storing learned information obtained as a result of learning performed by the learning means; and output means for converting the non-linguistic sign information or the stored learned information and for outputting the converted non-linguistic information or the stored learned information regarding the emotion of the user.