Here we look at the marking of the patient argument in typical transitive clauses (’David killed Goliath’, ‘The girl picked the flower’, etc.), i.e. what is often called direct object. We restrict our attention to full noun phrases, as pronouns are often treated in a special way.
We ask whether patient noun phrases may have case-marking or adpositional marking that distinguishes them from agents (i.e. accusative marking), and if so, under what conditions it occurs. (Of course, fixed word order may also distinguish agents and patients, but this is not considered patient marking here.) Note that by presence of marking, we mean possibility of marking. In many languages, patient marking is optional and need not occur where it can occur.