Balkan Slavic literary production between the mid-16th and mid-19th centuries is characterised by the transition from the medieval tradition to the gradually emerging norms of the later literary languages. This transition manifests itself in two domains: linguistically, as concerns the increasing replacement of Church Slavonic by vernacular elements and structures, while the literary development becomes apparent in the altering inventory of text genres. Arguing that both tendencies go hand in hand, the present paper illustrates how certain linguistic changes can be functionally interpreted against the background of literary innovations. These changes concern the usage of forms and structures that had not been customary in the older tradition, and the appearance of new functions for morphosyntactic categories and syntactic structures. The examples discussed include the functional extension of ‘perfect-like’ forms (lparticiple + ‘to be’), the usage of edin ‘one’ as indefiniteness marker, different ways of reporting speech and parenthetical insertions. What these innovations have in common is the introduction of a narrating instance, i.e. a feature that is constitutive of texts with a primarily narrating, instead of descriptive or pedagogic, function. These processes are illustrated from a diachronic point of view on the example of different versions of the Life of Petka Tărnovska, and from a synchronic perspective on the example of selected texts from Pop Punčo’s Sbornik.