In 2005, Arnold Zwicky posited two misapprehensions about language: the Recency Illusion, or the false idea that certain language variation is new, and the Frequency Illusion, the erroneous belief that a particular word or phrase occurs often. Since their conception, these concepts have received widespread attention in popular scientific linguistics, but quantitative research investigating their application is scarce. The purpose of this paper is to provide an empirical investigation of Zwicky’s proposed illusions. It does so by collecting statements about recency (‘this word is new’) and frequency (‘this construction occurs often’) from a database of Dutch prescriptive publications (1900–2018). I assessed their accuracy by comparing them to linguistic sources, including dictionaries, and usage corpora and other data. Our research showed that recency statements were rare, but that frequency statements, especially using high frequency terms such as vaak (‘often’), were commonplace. Compared to usage, most prescriptive recency and frequency statements for both lexis and grammar indeed constituted Zwickian illusions. This seems partly due to genuine erroneous or unsupported beliefs by authors, but also partly to prescriptive genre conventions and rhetorical choices. Our explorative research highlights the complex usage–prescriptivism interface, and argues for more research into this aspect of language perceptions.