From the beginning of the nineteenth century constant progress was made in comparative studies (e.g., work on exceptions to Rask’s and Grimm’s sound laws: Lottner, Grassmann, Verner). In 1870 young German scholars, the Junggrammatiker (‘Neogrammarians’) declared in their programmatic statement (by Osthoff and Brugmann) that a change ‘in the face of comparative linguistics’ was necessary for it to gain the reliability of the natural sciences. The main principles of their credo were: language is localized/observable in the individual: to understand how speech lives and develops, linguists have to pay attention to speakers and the speaking process; psychological factors at work in language change have to be considered; sound laws operate without exception; analogical changes explain violations of sound laws. The last two axioms were criticized (e.g., Curtius), but the neogrammarian contribution to the advancement of linguistics was recognized and their principles followed: cf. Sievers's work, the creation of neogrammarian periodicals, Brugman and Delbruck’s Grundriss and Paul’s Prinzipien, a methodological tool for historical studies for decades. By the end of the century, language studies greatly expanded in German universities. The most important neogrammarian center was Leipzig University, where foreigners such as Saussure, and later Bloomfield, studied.