Tree Model - Computational Phylogenetics in Historical Linguistics

Computational Phylogenetics in Historical Linguistics

The comparative method compares features of various languages to assess how similar one language is to another. The results of such an assessment are data-oriented; that is, the results depend on the number of features and the number of languages compared. Until the arrival of the computer on the historical linguistics landscape the numbers in both cases were necessarily small. The effect was of trying to depict a photograph using a small number of large pixels, or picture units. The limitations of the Tree Model were all too painfully apparent, resulting in complaints from the major historical linguists. The Wave model was devised as one answer.

In the late 20th century, linguists began using software intended for biological classification to classify languages. Programs and methods became increasingly sophisticated. In the early 3rd millennium the Computational Phylogenetics in Historical Linguistics (CPHL) project, a consortium of historical linguists, received funding from the National Science Foundation to study phylogenies. The Indo-European family is a major topic of study. As of January, 2012, they had collected and coded a "screened" database of "22 phonological characters, 13 morphological characters, and 259 lexical characters," and an unscreened database of more. Wordlists of 24 Indo-European languages are included. Larger numbers of features and languages increase the precision, provided they meet certain criteria. Using specialized computer software, they test various phylogenetic hypotheses for their ability to account for the characters by genetic descent.