A relay apparatus includes a characteristic information storage unit, a first dictionary information storage unit, a first selection unit, and a first conversion unit. The characteristic information storage unit stores pieces of terminal information in association with respective pieces of characteristic information, each indicating a characteristic of a user. The first dictionary information storage unit stores the pieces of characteristic information in association with respective pieces of first dictionary information used for converting voice data into text data. The first selection unit selects, when voice data is received from a second communication terminal to communicate with a first communication terminal, the characteristic information associated with the terminal information for identifying the second communication terminal and selects the first dictionary information associated with the selected characteristic information. The first conversion unit converts the voice data received from the second communication terminal to text data using the first dictionary information.