1. A method for updating a dynamic dictionary for use in compressions and decompression of messages, the method comprising the steps of: a. receiving a message; b. determining one or more matching sequences contained in the message that each have a corresponding match in a first dictionary; c. determining which matching sequences are contiguous to each other in the message; and d. creating in the dynamic dictionary at least one new combined expression comprising two or more matching sequences determined to be contiguous to each other within the message.