A server machine receives an input string of characters from a client machine, and the string includes at least one abbreviated substring preceded and followed by word delimiters. Each abbreviated substring represents an expanded substring. The server machine automatically finds one of the abbreviated substrings based on the preceding and following word delimiters, determines that it is one of a set of abbreviated substrings, and produces an expanded version of the string of characters with the abbreviated substring replaced by its expanded substring. The case of the beginning character of the expanded substring can be the same as that of the abbreviated substring. The expanded substring can depend on time, such as the current time.