Abstract: A device (110) used for composing, compressing and transmitting messages by way of a data network (100) comprises means (116) for employing predictive text entry during composition of a message (MSG) and compressing the composed message for transmission. Increased redundancy and improved compression efficiency result from having the predictive text entry program (201) suggest character strings (207) derived from a corpus of messages (204) that serves also as a basis for a statistical model (206) used for compression. A messaging system comprising the composition device (110) and a device for receiving and decompressing the message may comprise a messaging (MSG) hub (108) for decompressing messages (MSG) from the composing device and reformatting them, for example as e-mail messages (E-MSG), before transmitting them to the addressee (112, 113, 114, 115) and, conversely, compressing messages from the addressee using a similar corpus of messages (204) before transmitting them to the composing device (110).