A multilingual communication system that provides translation-enabled terminal-to-terminal communication, the multilingual communication system comprising: a participating terminal connection unit configured to connect a plurality of terminals participating in the communication, acquire language information set for each of the terminals from an operation system or a browser in the terminal to recognize a use language used in the terminal from the language information and automatically select the language used by a user, define for each terminal a terminal message box for the communication, in which transmission messages from a terminal and reception messages to the terminal are described so as to be displayable in a time-series manner, and correlate the use language of the terminal with the terminal message box; a box coupling setting unit configured to set coupling between a first terminal message box and a second terminal message box so that a transmission message written in the first terminal message box defined for a first terminal is translated using a use language of the first terminal message box as a translation source language and using a use language of the second terminal message box defined for a second terminal as a translation destination language and is written in the second terminal message box as a reception message; and a box coupling execution unit configured to, when a transmission message is written in the first terminal message box from the first terminal, translate the transmission message from the translation source language to the translation destination language according to the coupling, write the translated transmission message in the second terminal message box as a reception message, and display the reception message on the second terminal. a participating terminal connection unit configured to connect a plurality of terminals participating in the communication, acquire language information set for each of the terminals from an operation system or a browser in the terminal to recognize a use language used in the terminal from the language information and automatically select the language used by a user, define for each terminal a terminal message box for the communication, in which transmission messages from a terminal and reception messages to the terminal are described so as to be displayable in a time-series manner, and correlate the use language of the terminal with the terminal message box; a box coupling setting unit configured to set coupling between a first terminal message box and a second terminal message box so that a transmission message written in the first terminal message box defined for a first terminal is translated using a use language of the first terminal message box as a translation source language and using a use language of the second terminal message box defined for a second terminal as a translation destination language and is written in the second terminal message box as a reception message; and a box coupling execution unit configured to, when a transmission message is written in the first terminal message box from the first terminal, translate the transmission message from the translation source language to the translation destination language according to the coupling, write the translated transmission message in the second terminal message box as a reception message, and display the reception message on the second terminal.