1. In an information processing system including an execution unit having a memory, a bulk storage and a workstation connected thereto operated by a user, said workstation including a keyboard connected to a display screen for inputting command and working text information to said display screen for display thereon, a multilingual processor for building screen images on said display screen and for decoding multilingual, user defined commands, comprising: a document library stored in said bulk storage device including a plurality of language documents and at least one user document; said language documents each characterizing a selected language and including an initialization records portion, a displayable components portion and an executable components portion including an sequence of elementary commands defined by the user; a language document selector means, for accessing a selected one of said plurality of language documents in response to a user language selection input from said keyboard specifying that commands are to be input to said keyboard and messages are to be displayed on said display screen in a first one of said selected languages; an initialization processor means, for accessing said initialization records portion from a first one of said language documents for storage in said memory, to provide a set of constant words to be continuously displayed on said display screen in said first language; a message processor means, for accessing said displayable components portion from said first one of said language documents, for the real-time display of messages on said display screen in said first language; a command processor means for accessing said sequence of elementary commands defined by the user in said executable components portion of said first one of said language documents in response to a user command input in said first selected language to said keyboard, for decoding said user command input in said first language; said language document selector means accessing a second selected one of said plurality of language documents in response to a second user language selection input from said keyboard specifying that commands are to be input to said keyboard and messages are to be displayed on said display screen in a second one of said selected languages; whereby multilingual processing is achieved for screen image build and decoding of user defined commands.