Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Partial phylogenetic tree of the IE languages showing the words that the languages use for the meaning ‘bird’, coded to identify cognate classes. Squares along the branches identify regions of the tree where new cognate classes might have arisen, although the analysis strategy integrates over all possible ancestral transitions [14] and so is not conditional upon any particular set of them.
