Changes in the style and content of Australian election campaign speeches from 1901 to 2016: a computational linguistic analysis

There have been significant social and political changes in Australian society since federation in 1901. The issues that are considered politically salient have also changed significantly. The purpose of this article is to examine changes in the style and content of election campaign speeches over the period 1901 – 2016. The corpus consists of 88 election campaign speeches delivered by the Prime Minister and Opposition leader for the 45 elections from 1901 to 2016. I use natural language processing to extract from the speeches a number of linguistic variables which serve as independent variables and use the year of delivery as the dependent variable. I then use use machine learning to develop a regression model which explains 77 per cent of the variance in the dependent variable. Examination of the salient independent variables shows that there have been significant linguistic changes in the style and content of election speeches over the study period. In particular, speeches have become less linguistically complex, less analytical, more focused on work and the home, and contain more social references. I discuss these changes in the context of changes in Australian society over the study period