Natural language change or prescriptive influence?

This paper investigates five morphological Americanisms in their diachronic development since 1810 on the basis of data from the Corpus of Historical American English, namely the past tense forms of THRIVE, DIVE, PLEAD, DRAG, and SNEAK. THRIVE is a clear case of an irregular verb becoming regular; in the other four lexemes (DIVE, PLEAD, DRAG and SNEAK), the irregular forms are actually a new development, as the corpus analysis can show. Present-day Americanisms can thus be the result of different historical processes that diverge from British English: differential speed in the same process, or change in a different direction. In both cases of change, it is a valid question to ask whether they might have been the result of prescriptive pressure. In order to investigate the question in how far prescriptive grammars may have influenced this trend towards more regular or towards newly irregular forms, my corpus-linguistic data is correlated with changing recommendations in historical grammar books of English, based on a quantitative investigation of my collection of 258 grammars. I propose that prescriptive influence both on the regularization of THRIVE and on the process of ‘irregularization’ of DIVE, PLEAD, DRAG and SNEAK is minimal, and that we are most likely dealing with genuine changes from below. These changes are then, with some time lag, reflected in the (not so) prescriptive grammars of the time.