Differential subject marking without ergativity

While differential object marking seems to be widespread and is well represented in the linguistic literature, differential subject marking appears to be much less common. Burmese is one example of a language that marks some, but not all subjects, depending on a number of pragmatic factors. This phenomenon is widespread in Tibeto-Burman languages, but Burmese apparently differs from these in not having an underlying ergative alignment or an agentive source of the subject marker, suggesting that there are other sources for DSM than the ones identified in the literature. This study looks at the functions of the marker ká with subjects in colloquial Burmese and discusses factors favoring its occurrence and possible paths of its development.