Metronome: tracing variation in poetic meters via local sequence alignment
Ben Nagy, Artjoms Šeļa, Mirella De Sisto, Petr Plecháč
TL;DR
Metronome tackles the challenge of tracing metrical relationships across languages and historical periods by converting poems into sequences over a minimal four-letter prosodic alphabet and applying local sequence alignment. The approach, grounded in Smith-Waterman alignment, yields a distance metric that supports clustering and cross-linguistic comparison without requiring predefined evolutionary models. Through three cross-language case studies and a cross-linguistic meter evaluation, the paper demonstrates the method's ability to reveal structural similarities and divergences in metrical organization, while releasing an open-source Python package for reproducible analysis. This work provides a scalable, theory-leaning tool for historical and comparative versification research, enabling distant reading of meter across corpora and traditions.
Abstract
All poetic forms come from somewhere. Prosodic templates can be copied for generations, altered by individuals, imported from foreign traditions, or fundamentally changed under the pressures of language evolution. Yet these relationships are notoriously difficult to trace across languages and times. This paper introduces an unsupervised method for detecting structural similarities in poems using local sequence alignment. The method relies on encoding poetic texts as strings of prosodic features using a four-letter alphabet; these sequences are then aligned to derive a distance measure based on weighted symbol (mis)matches. Local alignment allows poems to be clustered according to emergent properties of their underlying prosodic patterns. We evaluate method performance on a meter recognition tasks against strong baselines and show its potential for cross-lingual and historical research using three short case studies: 1) mutations in quantitative meter in classical Latin, 2) European diffusion of the Renaissance hendecasyllable, and 3) comparative alignment of modern meters in 18--19th century Czech, German and Russian. We release an implementation of the algorithm as a Python package with an open license.
