In generative linguistics, Burzio's generalization is the observation that a verb can assign a theta role to its subject position if and only if it can assign an accusative case to its object. Accordingly, if a verb does not assign a theta role to its subject, then it does not assign accusative case to its object. The generalization is named after Italian linguist Luigi Burzio, based on work published in the 1980s, but the seeds of the idea are found in earlier scholarship. The generalization can be logically written in the following equation:
Burzio’s generalization has two major consequences:
Burzio describes the intransitive occurrence of ergative verbs in the generalization that bears his name:
Burzio’s observations led to two separate classes of intransitive verbs. Burzio claimed that intransitives are not homogenous and exemplified this observation with the following data from Italian:
Both of the verbs in 1a and 1b are classified as intransitives, they take only one predicate. However, what led Burzio to claim that the class of intransitives should be further divided was the distribution of Ne (of-them).
The different behaviour of these two intransitive verbs led to the hypothesis that the class of verbs known as intransitives were divided. Burzio argued that due to the grammatical differences between 2a and 2b, the underlying structures of 1a and 1b must be different.
In Italian, it is assumed that there is free subject inversion, which means that if a subject appears pre-verb then it will have a post-verb counterpart. The data in (3) demonstrates this assumption:
Burzio classified the subjects such as in 3b as i-subjects (inverted subjects). It turns out that Ne-Cliticization (Ne-Cl) is only possible with a direct object, but upon further observation Ne-Cl is also possible with i-subjects that are related to a direct object, such is the case with inherently passive verbs.
The distribution of Ne and auxiliary "essere" motivated the existence of a class of intransitive verbs named ergative verbs. This class of verbs subcategorizes for direct objects and does not assign agent theta roles. The deep structure (d-structure) objects are equal to the surface structure (s-structure) subjects. A distributional test for ergativity is whether or not it can take a Ne-Cl (see distributional tests below).