Mapping the information structure in Early Modern Bulgarian clauses with the particle TA

Bulgarian texts from the 17th century display the particle ta that seems to behave as some kind of complementizer, topic and information focus marker, all at once. This is different from Modern Bulgarian, where the same particle behaves either as a complementizer or as a narrative connector. We argue that intra-clausal ta in these texts spells out the cluster of features [topic], [force], and acts as a syncretic head that inherits the features of C. This analysis has empirical and theoretical advantages in accounting for diachronic changes in the computation of the left periphery. Notably, two representations were at work in Early Modern Bulgarian: one in which Top/ta inherits the features of C, and one in which null Top is associated with [topic] only and is irrelevant to the C-to-T feature transfer. Modern Bulgarian has only the latter, due to the loss of the [topic] feature of ta.