Variation of sentence length across time and genre

2018-10-23

Studies in Corpus Linguistics

AI Summary

This study investigates whether mean sentence length in written English has consistently decreased over time (1810–2000), using the Corpus of Historical American English (COHA), and examines its relationship with grammatical change—particularly the decline of the non-finite purposive marker *in order to*—and genre evolution. Methodologically, it employs large-scale corpus querying, diachronic mixed-effects modeling, multivariate correlation analysis, and genre-normalized frequency computation. Results confirm a statistically significant reduction in mean sentence length; crucially, they reveal a robust cross-temporal association between this reduction and the declining use of *in order to*, with systematic genre-specific variation observed in news and fiction. Moving beyond descriptive sentence-length analyses, the study integrates syntactic change, register evolution, and macro-level sentence-length trends within a unified empirical framework. It thus offers both methodological innovation—through genre-aware diachronic modeling—and theoretical advancement for historical syntax.

Technology Category

• Natural Language Processing: Sentiment Analysis, Stylistic Analysis, and Argument Mining
• Cognitive Modeling & Cognitive Systems: Computational Creativity
• Knowledge Representation and Reasoning: Common-Sense Reasoning

Application Category

• Web Mining and Content Analysis: Models for Web evolution
• Social Networks and Social Media: Generative AI / large language models and their impact on social systems
• Semantics and Knowledge: Methods, algorithms and applications for the development of semantic models, knowledge graphs and other forms of structured data models with machine-interpretable semantics

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.

Problem

• Analyze sentence length variation over time
• Test decline in English sentence length
• Link sentence length to syntactic changes

Innovation

• Analyzes COHA corpus diachronically
• Tests sentence length decrease trend
• Links syntax changes to sentence length