An automated sound correspondence-recognition program developed by the authors is applied to a data set consisting of standardized word lists for over half of the world's languages. Online appendices present the results in a compendium of 692 recurrent sound correspondences that contains information about the frequency of occurrence of each correspondence. Applications of the compendium to historical linguistics are proposed. For example, the catalog of correspondences and frequencies facilitates objective assessment of the commonness or rarity of shared phonological innovations cited as evidence for language-family subgrouping. In another analysis, correspondence frequency is used to measure the degree of similarity between different sounds, yielding models for classifying consonants and vowels that substantially agree with articulatory properties. Correspondence-based similarities are also compared with measurements of sound similarity involving factors such as perceptual confusions, speech errors, and cooccurrence patterns in synchronic phonological rules. Sound similarity discerned from both the perception and production of speech is found to correlate to about the same extent with correspondence-based similarities.