Surrey Defectiveness Database

The term 'defectiveness' refers to gaps in inflectional paradigms — specifically, gaps which do not appear to follow from natural restrictions imposed by meaning or function. The Typological Database on Defectiveness illustrates different types of defective paradigm according to various morphological and morphosyntactic parameters. The Cross-linguistic Database on Defectiveness looks at the prevalence of inflectional defectiveness in a controlled sample of genetically and geographically diverse language. 

The Surrey Cross-linguistic Database on Defectiveness provides an impression of the prevalence of inflectional defectiveness in the languages of the world using a stratified sample of 100 languages.