6. The device according to claim 1 , further comprising: an utterance error occurrence probability information storage unit configured to store utterance error occurrence probability, which is a probability of the word causing the utterance error, wherein the utterance error occurrence determining unit determines whether each word causes the utterance error, on the basis of the utterance error occurrence probability.
6. The device according to claim 1 , further comprising: an utterance error occurrence probability information storage unit configured to store utterance error occurrence probability, which is a probability of the word causing the utterance error, wherein the utterance error occurrence determining unit determines whether each word causes the utterance error, on the basis of the utterance error occurrence probability. 7. The device according to claim 6 , wherein the utterance error occurrence probability depends on the frequency of use of the word causing the utterance error, the degree of difficulty in meaning, or a difficulty in utterance during reading.