The direct case is used for intransitive clauses. In transitive clauses using the default grammatical voice of Tagalog, the direct marks the patient (direct object) and the indirect marks the agent, corresponding to the subject in English. In the more marked voice the reverse occurs, with the direct marking the agent and the indirect marking the patient.
Because the base form of the clause is superficially similar to the passive voice in English, this has led to a misconception that Tagalog is spoken primarily in the passive voice. It is also superficially similar to ergative languages such as those of Australia, so Tagalog has also been analyzed as an ergative language.
However, the English passive clause is intransitive, and likewise in ergative languages one of the voices forms an intransitive clause, whereas in Tagalog both voices are transitive, and so align well with neither nominative–accusative languages such as English nor with ergative languages.
The central feature of verbs in Tagalog and other Philippine languages is the trigger system, often called voice or focus. In this system, the thematic relation of the noun marked by the direct-case particle is encoded in the verb.In its default unmarked form, the verb triggers a reading of the direct noun as the patient of the clause. In its second most common form it triggers the noun as the agent of the clause. Other triggers are location, beneficiary, instrument, reason, direction, and the reciprocal.
