Editing Mass comparison (section)

=== Position of Greenberg's detractors ===

Since the development of [[comparative linguistics]] in the 19th century, a linguist who claims that two languages are related, whether or not there exists historical evidence, is expected to back up that claim by presenting general rules that describe the differences between their lexicons, morphologies, and grammars. The procedure is described in detail in the [[Comparative method (linguistics)|comparative method]] article.

For instance, one could demonstrate that [[Spanish language|Spanish]] is related to [[Italian language|Italian]] by showing that many words of the former can be mapped to corresponding words of the latter by a relatively small set of replacement rules—such as the correspondence of initial ''es-'' and ''s-'', final ''-os'' and ''-i'', etc. Many similar correspondences exist between the grammars of the two languages. Since those systematic correspondences are extremely unlikely to be random coincidences, the most likely explanation by far is that the two languages have evolved from a single ancestral tongue ([[Latin]], in this case).

All pre-historical language groupings that are widely accepted today—such as the [[Indo-European languages|Indo-European]], [[Uralic languages|Uralic]], [[Algonquian languages|Algonquian]], and [[Bantu languages|Bantu]] families—have been established this way.