The "Bentley's Code Phrases" [ http://www.archive.org/details/bentleyscomplete00bentuoft ] first published in 1906 continued to be commonly used till the end of 1960's. That and other codes were widely used by commercial establishments - "coding" seems to have been popular then at grass root levels. If the 5 letter codes were well understood, popular and used widely, there are no reasons why the present coding done with computer languages based on 8 bit letters can't be used with the same ease by the general public. Coding languages need to start circulating widely among the public the way Bentley's Code ruled from 1906 to the 1960s.
