Lexicase is a type of dependency grammar originally developed beginning in the early 1970s by Stanley Starosta at the University of Hawaii. Dozens of Starosta's graduate students also contributed to the theory and wrote at least 20 doctoral dissertations using Lexicase to analyze numerous languages of Asia (Japanese, Mandarin, Vietnamese, Thai, Khmer, Tagalog, etc.), Europe (Greek, Russian, etc.), and Africa (Swahili and Yoruba).
Lexicase is a mononstratal (i.e. it is not a transformational grammar) X-bar grammar in which words are the heads of their own phrases (i.e. there are no assumed empty phrases). In Lexicase, words have features that determine the morphosyntactic distribution of their dependents. A primary goal of Lexicase is to provide a simple, transparent, disprovable means of testing cross-linguistic tendencies.
As a lexically focused theory, Lexicase has been used to identify verb subcategories in Korean, Russian, Thai, and Vietnamese, and noun subcategories in Khmer and Thai and to provide an overall language description of Pacoh in central Vietnam. Regarding arguments and clause structure, it has been used to explore case in Greek and Mandarin Chinese and transitivity and ergativity in Amis, an indigenous language in Taiwan and in Proto-Central Pacific Austronesian, among other other topics.