Zarphatic language

Zarphatic, or Judeo-French (Zarphatic: Tzarfatit), is an extinct Jewish language that was spoken by the French Jews of northern France and in parts of west-central Germany, such as Mainz, Frankfurt am Main and Aix-la-Chapelle. It was also spoken by French Jews who moved to Norman England. Some have conjectured that the language influenced the development of Yiddish.

Etymology
The term Zarphatic, coined by Solomon Birnbaum, comes from the Hebrew name for France, Tzarfat (צרפת), which was originally used in the Hebrew Bible as a name for the city of Sarepta, in Phoenicia. Unlike most other Jewish languages which had a lot of loan words from Hebrew, it had relatively few. This has led to the conclusion that it may not have been a far-distant language but, instead, a dialect of Old French.

Writing
Zarphatic was written using a variation of the Hebrew alphabet. It first appeared in this form in the 11th century in glosses of the Torah and Talmud written by the rabbis Moshe HaDarshan and Rashi. The language became secularised during the 13th century, becoming used in varied domains such as poetry, medicine, astronomy, and commerce.

Most linguists agree that Zarphatic was not fundamentally different from Old French, and that it was more of a writing system, literary tradition, and specific vocabulary that reflected the Jewish culture of the day. According to some researchers, it was different from the Christian majority dialect, and thus a specific Judeo-Romance language.

It seems that Zarphatic was probably never a vernacular language, and that the Jews of the area did not speak a differing language or dialect, at least not one distinguished by phonology or lexicon beyond that specific to a community. Rather, it acted more as a liturgical language, for exegesis and literature. Its primary use was for explanation and vulgarisation of biblical and rabbinical literature.

Extinction
Due to the constant persecution, killing and expulsion of Jews from France and other European  nations, the Zarphatic Language went extinct in the 14th century.