Expressive prefixes are a specific word-formation category, unknown in synchronic derivatology. It is about word-formation elements which are essentially prefixes, but which are not recognised as such in the structure of the word. They can be isolated only by word-formation and etymological analysis. In the present paper, this category is studied within the context of dialectal material provided by J. K. Koprivica’s Dictionary of the Banjani, Grahovo and Oputne Rudine Speech. It is concluded that the examined speech contains a considerable number of expressively prefixed forms. Many of them have developed word families (e.g. čeprljati ‘to dig, scratch’, čomrgiti se ‘to frown’, kovriježiti se ‘to be angry’, kovrlja...