Guttural R
Many Jewish immigrants to Israel spoke a variety of Arabic in their countries of origin and pronounced the Hebrew rhotic as an alveolar tap , similar to Arabic '. Gradually, many of them began pronouncing their Hebrew rhotic as a voiced uvular fricative , a sound similar or (depending on the Arabic dialect) identical to Arabic '. However, in modern Sephardic and Mizrahi poetry and folk music an alveolar rhotic continues to be used.
Medieval Hebrew
Mention should also be made of the letters preserved in the Cairo geniza, which reflect the Arabic-influenced Hebrew of medieval Egyptian Jewry. The Arabic terms and syntax that appear in the letters constitute a significant source for the documentation of spoken medieval Arabic, since Jews in Islamic lands tended to use colloquial Arabic in writing rather than classical Arabic, which is the Arabic that appears in Arabic medieval sources.