Why Do Secret Languages Exist?

Many famous secret languages have been invented during wars and conflicts, and are usually called codes. With codes, messages are encoded (put into code), sent, and then decoded (taken out of code).

During a war each side needs to send and receive secret messages. These messages often contain important information such as when and where attacks are to be made. The messages have to be put into code so that if they are intercepted by the enemy, their meaning cannot be understood. If one side manages to understand the way a code works - or break it - they will be able to find out their enemy's secret plans.