LexicoStatistical

Lexicostatistics is a method used in historical linguistics to estimate the divergence time between related languages. It is based on the assumption that the rate of vocabulary replacement is relatively constant over time. The core of the method involves comparing lists of basic vocabulary words, such as those for body parts, natural phenomena, and common verbs, across different languages.

The lexicostatistical approach typically uses a Swadesh list, a standardized set of 100 or 200 basic words. By counting the percentage of cognates (words with a common origin) in these lists between two languages, linguists can infer how long ago they diverged from a common ancestor. The higher the percentage of cognates, the more recently the languages are thought to have split.

A key component of lexicostatistics is the concept of a "glottochronology," which attempts to assign absolute dates to language divergence. This involves applying a calculated rate of vocabulary loss, often derived from known historical language splits, to the observed cognate percentages. However, the assumption of a constant rate of vocabulary change has been a subject of considerable debate and criticism within the field of linguistics.

Despite its limitations and the ongoing scholarly discussion, lexicostatistics remains a tool for generating hypotheses about language relationships and divergence times, particularly when other historical or comparative data is scarce. It provides a quantitative framework for exploring the deep history of language families.