Implemented is a communication with reasonably smooth conversation even between people having different proficiency levels in a common language. Included are a voice recognition unit (14) that acquires a speech rate of a speaker and recognizes a voice on a speech content; and a call voice processing unit (12) that processes a part of a voice recognition result based on a result of comparing the acquired speech rate with a reference speech rate, and transmits a video on which a text character image of the voice recognition result having been processed is superimposed to a communication terminal TM of the speaker.