Stability of meanings versus rate of replacement of words: an experimental test

TL;DR

This study empirically tests the relationship between word stability and replacement rates across Romance languages, confirming the validity of traditional inference methods and revealing differences in stability rankings among language families.

Contribution

It provides a direct test of stability versus replacement rates using Latin as a reference, refines the Glottochronology formula for item-dependent rates, and compares stability across language families.

Findings

Standard approach to infer replacement rates from stability is validated.

Revised Glottochronology formula accounts for item-dependent rates.

Stability rankings vary significantly among language families.

Abstract

The words of a language are randomly replaced in time by new ones, but it has long been known that words corresponding to some items (meanings) are less frequently replaced than others. Usually, the rate of replacement for a given item is not directly observable, but it is inferred by the estimated stability which, on the contrary, is observable. This idea goes back a long way in the lexicostatistical literature, nevertheless nothing ensures that it gives the correct answer. The family of Romance languages allows for a direct test of the estimated stabilities against the replacement rates since the proto-language (Latin) is known and the replacement rates can be explicitly computed. The output of the test is threefold:first, we prove that the standard approach which tries to infer the replacement rates trough the estimated stabilities is sound; second, we are able to rewrite the fundamental formula of Glottochronology for a non universal replacement rate (a rate which depends on the item); third, we give indisputable evidence that the stability ranking is far from being the same for different families of languages. This last result is also supported by comparison with the Malagasy family of dialects. As a side result we also provide some evidence that Vulgar Latin and not Late Classical Latin is at the root of modern Romance languages.