Abstract
This study investigates least delicate patterns of appraisal in two diachronic corpora of UK Parliament and U.S. Congress speeches over the last two centuries, focusing on diachronic changes and trends of systemic probabilities of least delicate engagement and attitude polarity. Based on computational algorithms that automatically extract appraisal instances and intersections from the two corpora, the comparative analysis carried out in this paper incorporates several statistical methods, including homogeneity or 'change-point' tests, Mann-Kendall trend analysis, and time-series Correspondence Analysis. The results indicate that, in both corpora, probabilities of monoglossic as well as attitudinal patterns (as opposed to neutral ones) follow statistically significant upward trends. In addition, positive polarity is increasing steadily, especially in the U.S. Congress. appraisal intersections are also dynamically changing depending on changes in sociopolitical circumstances. More specifically, in the formative and early years during which party conflicts were intensified, heteroglossic patterns are favored. In war and post-war periods, monoglossic patterns are more associated with neutral polarity. In recent decades, during which political polarization hit a peak, monoglossic patterns begin to favor attitudinal polarity. These findings are discussed in terms of possible causal and correlational interpretations, limitations and directions for future research.