Yehoshua Mordechai Lifshitz (1828–1878), who is considered the father of Yiddishism and Yiddish lexicography, circulated an essay entitled “The Four Classes” (Yiddish: di fir klasn די פיר קלאסן) in which he referred to Yiddish as a completely separate language from both German and Hebrew and, in the European context of his audience, the "mother tongue" of the Jewish people. In this essay, which was eventually published in 1863 in an early issue of the influential Yiddish periodical Kol Mevasser, he contended that the refinement and development of Yiddish were indispensable for the humanization and education of Jews. In a subsequent essay published in the same periodical, he also proposed Yiddish as a bridge linking Jewish and European cultures. Scholar Mordkhe Schaechter characterizes Lifshitz as "[t]he first conscious, goal-oriented language reformer" in the field of Yiddish, and highlights his pivotal role in countering the negative attitudes toward the language propagated within the Haskalah, or Jewish Enlightenment movement:
Although an adherent of the Enlightenment, [Lifshitz] broke with its sterile anti-Yiddish philosophy, to become an early ideologue of Yiddishism and of Yiddish-language planning. He courageously stood up for the denigrated folk tongue, calling for its elevation and cultivation. He did this in the form of articles in the weekly Kol-mevaser (in the 1860s) and in his excellent Russian-Yiddish and Yiddish-Russian dictionaries [...].