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.


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.

Analyze quickly

Cog allows you to quickly produce results by automating many of the steps of the word list comparison process:

  • IPA-based segmentation: automatically splits words in to segments
  • Syllabification: automatically marks syllables
  • 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


Cog allows you to visualize your results from many different perspectives. Cog will automatically generate the following types of visual representations:

  • Radial trees
  • Dendrograms
  • Network graphs
  • Similarity matrices
  • Geographical maps