What Germanic language was once the most commonly-spoken language among European Jews?
German language German language German ( ) is a West Germanic language that is mainly spoken in Central Europe. It is the most widely spoken and official or co-official language in Germany, Austria, Switzerland, South Tyrol (Italy), the German-speaking Community of Belgium, and Liechtenstein. It is also one of the three official languages of Luxembourg and a co-official language in the Opole Voivodeship in Poland. The languages which are most similar to German are the other members of the West Germanic language branch: Afrikaans, Dutch, English, the Frisian languages, Low German/Low Saxon, Luxembourgish, and Yiddish. There are also strong similarities in vocabulary
Germanic parent language preceded the application of Grimm's Law. Germanic parent language In historical linguistics, the Germanic parent language (GPL) includes the reconstructed languages in the Germanic group referred to as Pre-Germanic Indo-European (PreGmc), Early Proto-Germanic (EPGmc), and Late Proto-Germanic (LPGmc), spoken in the 2nd and 1st millennia BC. The less precise term "Germanic", that appears in etymologies, dictionaries, etc., loosely refers to a language spoken in the 1st millennium AD, proposedly at that time developing into the group of Germanic languages—a stricter term for that same proposition, but with an alternative chronography, is "Proto-Germanic language". As an identifiable neologism, "Germanic parent language"