Indo-European languages tree by Levenshtein distanceM. Serva1 and F. Petroni2
1 Dipartimento di Matematica, Università dell'Aquila - I-67010 L'Aquila, Italy
2 GRAPES, B5, Sart Tilman - B-4000 Liège, Belgium
received 17 October 2007; accepted in final form 30 January 2008; published March 2008
published online 29 February 2008
The evolution of languages closely resembles the evolution of haploid organisms. This similarity has been recently exploited (GRAY R. D. and ATKINSON Q. D., Nature, 426 (2003) 435; GRAY R. D. and JORDAN F. M., Nature, 405 (2000) 1052) to construct language trees. The key point is the definition of a distance among all pairs of languages which is the analogous of a genetic distance. Many methods have been proposed to define these distances; one of these, used by glottochronology, computes the distance from the percentage of shared "cognates". Cognates are words inferred to have a common historical origin, and subjective judgment plays a relevant role in the identification process. Here we push closer the analogy with evolutionary biology and we introduce a genetic distance among language pairs by considering a renormalized Levenshtein distance among words with same meaning and averaging on all words contained in a Swadesh list (SWADESH M., Proc. Am. Philos. Soc., 96 (1952) 452). The subjectivity of process is consistently reduced and the reproducibility is highly facilitated. We test our method against the Indo-European group considering fifty different languages and the two hundred words of the Swadesh list for any of them. We find out a tree which closely resembles the one published in Gray and Atkinson (2003), with some significant differences.
87.23.Ge - Dynamics of social systems.
87.23.Kg - Dynamics of evolution.
89.75.Hc - Networks and genealogical trees.
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