A substitution cipher is a code where each English letter is substituted with another symbol. These symbols could be anything from emoticons to numbers.
A substitution cipher is easy to create, and easy to decipher. One of the easiest ways to write in a cipher is to change the font on your computer to something unrecognizable, such as “wingdings” or “webdings”.
To decipher, simply highlight and change it into a recognizable font:
Deciphered: this is an example of a sentence written in a cipher
(Or you can print it up with a key.)
Whenever messages are encoded or in a fictional “foreign language” in middle grade novels, it is almost always simply English using a substitution cipher. Examples are found in Dan Gutman’s Genius Files, Clifford B. Hicks’ Alvin’s Secret Code, and Eoin Colfer’s Artemis Fowl. Video games, too, use substitution ciphers, such the “alien writing” in Aquaria.