The goal of this paper is threefold: (i) to present some practical aspects of using the full-text version of the Corpus of Historical American English (COHA), the largest diachronic multi-genre corpus of the English language, in the investigation of a linguistic trend of change; (ii) to test a widely held assumption that sentence length in written English has been steadily decreasing over the past few centuries; (iii) to point to a possible link between changes in sentence length and changes in English syntactic usage. The empirical proof of concept for (iii) is provided by the decline in the frequency of the non-finite purpose subordinator in order to . Sentence length, genre and the likelihood of occurrence of in order to are shown to be interrelated. Variation of sentence length across time and genre Pre-final submission which appeared as: Rudnicka, Karolina. 2018. Variation of sentence length across time and genre. In Diachronic Corpora, Genre, and Language Change [Studies in Corpus Linguistics 85], Richard Jason Whitt (ed.), 220-240. Amsterdam & Philadelphia: John Benjamins. https://www.benjamins.com/catalog/scl.85 Karolina Rudnicka University of Freiburg Variation of sentence length across time and genre: influence on the syntactic usage in English Abstract The goal of this paper is threefold: i) to present some practical aspects of using full-text version of Corpus of Historical American English (COHA) , the largest diachronic multi-genre corpus of the English language, in the investigation of a linguistic trend of change; ii) to test a widely held assumption that sentence length in written English has been steadily decreasing over the past few centuries; iii) to point to a possible link between the changes in sentence length and changes in the English syntactic usage. The empirical proof of concept for iii) is provided by the decline in the frequency of the non-finite purpose subordinator in order to. Sentence length, genre and the likelihood of occurrence of in order to are shown to be interrelated. Keywords: sentence length; language change; semicolon; mega-corpora; Late Modern English, in order to Variation of sentence length across time and genre On the other hand, it is becoming easier to read “because of its declining sentence length and number of clauses per sen tence”. The work of Dorgeloh (2005) on patterns of agentivity and narrativity in early science discourse, adds a few more observations on the development of language of science from the 15th century to the present, and on the factors that shaped the way scientific texts look like today. In her work ( 2005: 92) she claims that “ modern science texts tend to nominalise the experience and to impersonalise the argument ”, whereas in the past it was typical for the narrative and the argument to be based on personal reference. The observations concerning the more complex and compact noun phrases and the decrease in the number of clauses per sentence are further supported by the research of Hundt et al. (2012 : 224), which also focuses on scientific discourse. Additionally, their research notes that the marked decrease in the frequency of relative clauses coincides with a marked decrease of sentence length occurring around the beginning of the twentieth century (2012: 225). A large part of the recent research dealing with sentence length decrease focuses on newspaper language. Westin (2002) provides statistically significant evidence for this effect in a wide range of English newspapers, such as The Times, Guardian and Daily Telegraph for the period 1900 -2000. Additionally to the sentence length itself, she also investigates sentence length distributions in the texts from particular years. One of the observations she makes is that “The shortest sentences, from 1 to 10 words, increased in number, from 5.7% in 1900 to 16.6% in 1993” (Westin 2002: 81). Westin concludes that if we assume there is a relation between sentence length and sentence complexity, “it is obvious that the complexity of the sentences in English Variation of sentence length across time and genre sentence length decrease, and if the possible explanations for this decrease would be similar cross-linguistically. Language Corpora Davies, Mark. (2008-). The Corpus of Contemporary American English (COCA): 520 million words, 1990-present. Available online at http://corpus.byu.edu/coca/ Davies, M ark. (2010-). The Corpus of Historical American English (COHA): 400 million words, 1810- 2009. Available online at https://corpus.byu.edu/coha/ References Biber, Douglas & Conrad, Susan. 2009. Register, Genre, and Style . Cambridge: Cambridge University Press. Biber, Douglas & Gray , Bethany. 2010. Challenging stereotypes about academic writing: Complexity, elaboration, explicitness. Journal of English for Academic Purposes 9, 2-20. Davis, Edith A. 1937. Mean sentence length compared with long and short sentences as a reliable measure of language development. Child Development 8(1): 69-79. Dorgeloh, Heidrun. 2005. Patterns of agentivity and narrativity in early science discourse. In Opening windows in discourse and texts from the past , Janne Skaffari, Matti Peikola, Ruth Carroll, Risto Hiltunen & Brita Warvik (eds), 83-94. Amsterdam & Philadelphia: Benjamins. Fahnestock, Jeanne. 2011. Rhetorical Style: The Uses Of Language In Persuasion. New York: Oxford University Press. Fries, Udo. 2010. Sentence Length, Sentence Complexity and the Noun Phrase in 18th-Century News Publications. In Language Change and Variation from Old English to Late Modern