Cog is a tool for comparing languages using lexicostatistics and comparative linguistics techniques. It can be used to automate much of the process of comparing word lists from different language varieties.

• IPA-based segmentation: automatically splits words in to segments
• Stem identification: identifies prefixes and suffixes so that they can be ignored during comparison
• Word alignment: aligns segments between word pairs
• Sound correspondence identification: automatically identifies sound correspondences and the environments in which they occur
• Cognate identification: provides various methods for identifying cognates
• Lexical/phonetic similarity: calculates lexical/phonetic similarity for multiple language varieties
• Visualization: generates similarity matrices, hierarchical graphs (UPGMA, Neighbor-joining), and network graphs

The goal of Cog is to provide a framework for experimenting with different techniques for language variety comparison. It is intended to be used iteratively: run a comparison, analyze the results, refine the process, run the comparison again, and so on. Most steps in the process can be tailored. It currently only supports a few comparison techniques, but we hope to include many more in the future.