This project aims at exploring an extraordinary and highly valuable source for a new history of Dutch: the recently rediscovered collection of about 38,000 Dutch documents from the second half of the 17th to the early 19th centuries, comprising over 15,000 private letters, which were confiscated during the wars fought between The Netherlands and England. These so-called "sailing letters", though mere booty for privateers as well as for the British High Court of Admiralty at the time, nowadays represent priceless material for historical linguists of the 21st century. For the first time in history these letters allow us to gain access to the language of people from the middle and lower social classes: men and women, but also children. The groundbreaking research project proposed here will lead to a thorough revision of the traditional views of 17th- and 18th-century Dutch, which is largely based on analyses of published, mostly literary texts produced by professional - male - writers belonging to the higher social classes from the province of Holland. The project proposes to analyse the linguistic data from a socio-historical perspective, and will allow us to present a more complete view of the history of Dutch than ever before. By looking at language from the perspective of the language history from below we will consequently be able to complement current accounts of the history of Dutch from a non-standard perspective and thus fill gaps that it was previously simply impossible even to take into consideration.