monotransitivity

Monotransitivity is a valency pattern in predicate structure where a verb selects exactly one internal argument in addition to the external argument, producing a two-participant event. In practical terms, a monotransitive verb takes a single direct object (the patient) while the subject (the agent) remains the external argument.

This pattern is contrasted with intransitive verbs, which require no object, and with ditransitive verbs, which require two internal arguments such as a direct object and an indirect object (for example, a recipient or goal). Some verbs can also appear ambitransitively, behaving transitively in some contexts and intransitively in others, but monotransitives are defined by their requirement for one object.

In language typology, monotransitivity is a common and widely studied configuration. Morphology and syntax often reflect the direct object through case marking, agreement, or prepositional phrases, depending on the language. Some languages have clear, rigid valency patterns, while others permit flexibility or alternations between transitive and intransitive uses for the same verb.

Examples in English illustrate the pattern: eat an apple, read a book, build a house. Each of these verbs requires a single object to complete the predicate. By contrast, verbs like give or tell can be ditransitive, as in give the girl a book or tell him a story, which involve additional person-like arguments or prepositional phrases expressing recipients or goals.

Overall, monotransitivity is a fundamental concept in valency theory, helping to classify verbs by the number of core arguments they require and shaping how sentences are structured and interpreted.