There is no author named Jacques Barbary de Langlade. There is a person named
Charles de Langlade (1732-1828), who is a significant figure in the history of the American Midwest, particularly in the region that would become Wisconsin. However, he is not known for his writings, but rather his actions as a fur trader, interpreter, and military leader.
It is possible that you might be thinking of a different author or that the name you provided is a misremembered or misspelled version of someone else's name. If you could provide more context or details, I might be able to help you find the author you are looking for.