In order to be plain, language should be well-structured. This is the theory upon which the PLAIN LANGUAGE Game is based. It provides those who aspire to be legal drafters with practice in constructing well-structured statements - a useful skill for expressing clear legal norms. You have already encountered the underlining of part of the term 'well-structured', 'PLAIN LANGUAGE' and 'norm', and may be wondering about it The underlining of the first two letters of each word of a term indicates that the term is a defined term and that it is being used in its defined sense. Thus, a well-structured statement has the property of being well-structured in a defined sense of the term 'well-structured'. The term is defined by the following contextual definition. A statement is well-structured, IF AND ONLY IF the relationships between its constituent sentences are expressed by defined structural terms.
Allen, Layman E. "Clarifying Legal Drafting by Well-Structuring It: An Improved Version of the PLAIN LANGUAGE Game." In Electronic Law '82. Milton, UK: Society for Computers & Law, 1982.