A secundative language is a language in which the indirect objects of ditransitive verbs are treated like the direct objects of monotransitive verbs. This language type was called dechticaetiative in an article by Edward L. Blansitt, Jr., but that term did not catch on. Secundative languages contrast with indirective languages where then indirect object is treated in a special way.
Ditransitive verbs have two arguments other than the subject: a theme that undergoes the action and a recipient that receives the theme (see thematic role). In a secundative language, the recipient of a ditransitive verb is treated in the same way as the single object of a monotransitive verb, and this syntactic category is called primary object. The patient of a ditransitive verb is treated separately and called secondary object.
A language need not be entirely secundative in its structure. English is primarily indirective, as in the sentence The girl gave money to the boy. However, it has some verbs that work differently, e.g. provide (The project provides young people with work, where the recipient argument is treated like the monotransitive direct object).