For example, the career of the great German mathematician C. F. Gauss. His early works, written around 1800, were in Latin. By the end of his career in the 1840s, he wrote in German.
True, though I suspect this probably has more to do with the rise of German nationalism in the 1840s, including a few revolutionary unification attempts. The German language itself was a major political issue of the day.
https://en.m.wikipedia.org/wiki/German_nationalism