A number of recent studies of grammatical categories in English have identified regional and diachronic variation in the use of the present perfect, suggesting that it has been losing ground to the simple past tense from the eighteenth century onwards ( Elsness, 1997 , 2009 ; Hundt and Smith, 2009 ; and Yao and Collins, 2012 ). Only a limited amount of research has been conducted on non-present perfects. More recently, Bowie and Aarts’ (2012) study using the Diachronic Corpus of Present-Day Spoken English has found that certain non-present perfects underwent a considerable decline in spoken British English (BrE) during the second half of the twentieth century. However, comparison with American English (AmE) and across various genres has not been made. This study focusses on the changes in the distribution of four types of non-present perfects (past, modal, to-infinitival and ing-participial) in standard written BrE and AmE during the thirty-year period from the early 1960s to the early 1990s. Using a tagged and post-edited version of the Brown family of corpora, it shows that contemporary BrE has a stronger preference for non-present perfects than AmE. Comparison of four written genres of the same period reveals that, for BrE, only the change in the overall frequency of past perfects was statistically significant. AmE showed, comparatively, a more dramatic decrease, particularly in the frequencies of past and modal perfects. It is suggested that the decline of past perfects is attributable to a growing disfavour for past-time reference in various genres, which is related to long-term historical shifts associated with the underlying communicative functions of the genres. The decline of modal perfects, on the other hand, is more likely to be occurring under the influence of the general decline of modal auxiliaries in English.
Diversity in Primate External Eye Morphology: Previously Undescribed Traits and Their Potential Adaptive Value