born March 15, 1794, Giessen, Hesse-Darmstadt
died May 29, 1876, Bonn, Ger.
German linguist, regarded as the founder of Romance philology.
He began his career as a scholar of medieval Provençal poetry and taught literature at the University of Bonn from 1823 to the end of his life. Diez applied the methodology of comparative linguistics pioneered by Franz Bopp to the {{link=Romance languages">Romance languages . In his Grammar of the Romance Languages (1836–44) and Etymological Dictionary of the Romance Languages (1853), he demonstrated the relationship of "Vulgar" or Spoken Latin to Classical Latin and the evolution of Romance languages from Spoken Latin into their modern forms.