Detail #138: An ergative twist on topic-marking

Let us imagine a topic-prominent language that has a marker for its topics - say a suffix. Now, when the topic is the only noun present, it is unmarked.However, when a bare non-topic is present, disambiguation is necessary and the topic gets marked - however, several other types of noun-phrase may remain unmarked - subjects, objects, possessors and indirect objects. However, if all other present non-topics are marked by adpositions or explicit case markers, the topic may be unmarked.