Fig 1. Illustration of the contrast between aligned and nonaligned agent expressions in Hindi, which allows both types of expressions (for detailed examples see S1 Table).

In aligned expressions (used with imperfective aspect), unmarked noun phrases are compatible with both intransitive (“crouches”) and transitive sentences (“plants trees”). In nonaligned expressions (used with perfective aspect), unmarked noun phrases are only compatible with intransitive sentences (“crouched”) because in transitive sentences (“planted trees”) noun phrases are marked by an additional element “+x” (“ne” in Hindi).