Despite some excellent historical and contemporary research on the linguistic situation in the Shetland Islands, to date there have been no studies with an in-depth focus on a specific type of dialect-to-standard speech modification, known locally in Shetland as knappin. Specifically: as the speakers understand it, what is the precise definition of knappin and how might this feature be linked to dialect attrition? The concept of knappin is a widely debated and contentious issue within Shetland. Questions such as how, when and why does it occur, who does it, and whether its use is the final step to complete dialect levelling, have never been fully explored. This study addresses such questions by conducting a quantitative and qualitative sociolinguistic analysis of perceptions on dialect modification across the islands; with the aid of data collected from many hundreds of Shetlanders, and dialect speakers no longer resident. My results show that all dialect speakers are modifying their speech more frequently, for many reasons and in many different linguistic situations. While this is of some concern, closer analysis of dialect perceptions and attitudes, and the exploration of areas where the use of dialect is seen to be increasing, indicate that, despite regular and extensive modification, the dialect might not be as at risk as previous research has indicated.