Zipf's law and the grammar of languages: A quantitative study of Old and Modern English parallel texts

Abstract

This paper reports a quantitative analysis of the relationship between word frequency distributions and morphological features in languages. We analyze a commonly-observed process of historical language change: The loss of inflected forms in favour of ‘analytic’ periphrastic constructions. These tendencies are observed in parallel translations of the Book of Genesis in Old English and Modern English. We show that there are significant differences in the frequency distributions of the two texts, and that parts of these differences are independent of total number of words, style of translation, orthography or contents. We argue that they derive instead from the trade-off between synthetic inflectional marking in Old English and analytic constructions in Modern English. By exploiting the earliest ideas of Zipf, we show that the syntheticity of the language in these texts can be captured mathematically, a property we tentatively call their grammatical fingerprint. Our findings suggest implications for both the specific historical process of inflection loss and more generally for the characterization of languages based on statistical properties.