In linguistics, differential argument marking (DAM) is the phenomenon of a language's encoding a single grammatical function (e.g. subject or object) in different ways.
[3] However, in recent years there has been a growing interest in the great variety of differential marking patterns across the world's languages in both formal and functional linguistics.
[9] It also includes properties related to the event semantics, such as the affectedness of arguments or the level of volitionality or control.
[10] Finally, in many languages, differential marking is related to the status of arguments as either topical or focal.
[2] There appear to be cross-linguistic differences in the triggering factors depending on whether the subject (agent) or object (patient) is differentially-marked.
Examples of inherent properties that affect argument marking include the person, animacy and uniqueness features of a noun, which are often expressed as a hierarchy or scale.
Differential marking is also linked to information structure and the status of an argument as either topic or focus.
Differential marking of agents and patients appear to be affected by different information structure triggers.
Objects that are not topical cannot be marked with ta, for example when they have argument focus as the answer to a question, as in (4b).