The struggle between Yiddishism and Hebraism in the interwar Baltic states still awaits systematic investigation and requires the use of sources in many languages. Paul Ariste (1905–1990), a famous Estonian linguist and polyglot, learned Yiddish as a young man and remained fascinated with the language for his whole life. This case study of non-Jewish support of Yiddishism in Estonia examines the arguments Ariste used in a Yiddish-language speech in 1933 in the general context of Yiddishist ideology. A member of a small people himself, Ariste was mostly concerned with assimilation. Apparently he did not consider hebraisation of the diaspora a possibility and therefore did not see Hebrew as a serious rival of Yiddish. There are marked parallels between Estonian and Yiddish language planning problems in the interwar period: despite obvious differences in their sociolinguistic history, the languages faced somewhat similar problems. The language planning climate in both cases was characterised by sensitivity towards German. In Ariste’s view, German, attractive to Jews as a powerful language of high culture and a means of modernization, posed an ideological threat, but not a threat to Yiddish corpus planning, since Yiddish is different from German by definition. His advocacy of Yiddish differs from usual Yiddishist argumentation only in minor details. He might be compared to moderate Yiddishists.