Bishop Sprat, just quoted, laid praise on the young Royal Society for its plain use of language. He went so far as to say that ‘eloquence ought to be banish’d out of all civil Societies’. By eloquence, he meant language that sounds intelligent but fails to communicate any clear messages. The problem with eloquence is that only the individuals using the language fully understand what has been said. It is an exclusive form of communication. It is communication that works for those with the power and prestige to avoid searching analysis of what they have actually said. Put baldly, eloquence is language that does not work as a general medium of communication. It works instead as a means of bamboozling an audience, or intimidating them into silent approval.

This book asks as its principal question: how does language work in politics? In addition, and by extension, what impact does language have on the effectiveness of policy? The particular language interrogated in these pages is parliamentary legislation. This language is not prone to eloquence in the manner described by Sprat, but legislation can and does contain parts of speech that similarly fail to communicate clear meaning. The principal answers offered in these pages are: first, that legislative language has undergone major changes in form and function since 1900; and, second, that it increasingly takes a form that does not work at communicating clear policy instructions, with the implication of this second point being that indeterminate language in legislation undermines effective policy delivery. The book offers the first computer-assisted analysis of all 41.5 million words of parliamentary legislation enacted from 1900 to 2015.