This study applies the relexification hypothesis to the genesis of Yiddish. The author believes Yiddish began as a Sorbian dialect relexified to High German between the 9th-12th centuries. The present study, rich in data (much of it presented as entries to a projected etymological dictionary), also suggests new diagnostic tests for identifying relexification. The presence in Yiddish of East Slavic features (e.g. pseudo-dual, gender and plural suffix assignment) suggests that the descendants of the Judaized Khazars also relexified Kiev-Polessian (northern Ukrainian and southern Belarussian) in the 15th century to Yiddish and German. Yiddish is thus a mixed West-East Slavic language and the best proof that Khazar Jews were a major component in the ethnogenesis of the Ashkenazic Jews. Two dramatic findings are that by comparing Middle High German and Slavic vocabulary and derivational machinery, it is possible (a) to "predict" with high accuracy which German components could be accepted by Yiddish and (b) whether lexicon was most likely acquired in the first or second relexification phase or thereafter. Blockage of many Germanisms also necessitated reliance on Hebrew and invented Hebroidisms. Thus the study also contributes to an understanding of the genesis of (Slavic) Modern Hebrew, relexified from Yiddish in the 19th century.
From the contents: Introduction 1. The Relexification Hypothesis in Yiddish 2. Approaches to the study of Yiddish and other Jewish languages 3. Criteria for selecting German and Hebrew-Aramaic and for retaining Slavic elements in Yiddish 3.1. Component blending in Yiddish 3.2. The status of synonyms in Yiddish 3.3. Constructing an etymological dictionary for a relexified language 4. Evidence for the two-tiered relexification hypothesis in Yiddish:
From Upper Sorbian to German and from Kiev-Polessian to Yiddish 4.1. Sixteen observations about the relexification hypothesis in Yiddish
4.2. German morphemes and morpheme sets fully accepted by Yiddish 4.3. German morpheme sets blocked fully or in part in Yiddish by the Slavic substrata 4.4. The status of individual German morphemes and semantically related sets in Yiddish 4.5. Slavic gender and markers of plural and dual in Yiddish 4.6. Unrelexified Upper Sorbian and Kiev-Polessian elements in Yiddish 5. Future Challenges