This thesis presents an edition, translation and grammatical study of three Judaeo-Arabic manuscripts comprising the story Qiṣṣat al-Jumjuma The Story of the Skull , where typical features of the Jewish variety of Arabic, written and spoken in Egypt during the 19th century, are outlined. Special attention is paid to the dichotomy between the substandard varieties Middle Arabic, Non-Standard Cairene and spoken Egyptian Jewish Arabic on one side, and the varieties Standard Arabic and Standard Cairene on the other side. In addition to a number of acknowledged Jewish features attested in the material, new orthographic observations have been made of r as a reflex of emphatic l, e.g. in the spelling of allāh > arrāh God and ᵓiṭṭallaᶜ fī > ᵓiṭṭarraᶜ fī look closely at , never before attested in written form. Qiṣṣat al-Jumjuma was originally written in Arabic, only later to be translated to Judaeo-Arabic. The story is reminiscent of the qiṣaṣ al-ᵓanbiyāᵓ genre, which presents the pre-Islamic prophets from a popular, yet Islamic perspective. The Judaeo-Arabic versions, however, are evidently of Jewish influence, both in terms of narrative and linguistic content. The Judaeo-Arabic language comprises a continuum of Arabic varieties used by Jews living or formerly living in Arabic speaking countries. Their unique sociolinguistic situation makes Judaeo-Arabic relevant to the study of Arabic linguistics, most importantly the history of the Arabic language and its different written and spoken varieties. Written Judaeo-Arabic is closely connected to the substandard spectrum of written varieties called Middle Arabic, incorporating elements of Classical Arabic, dialect, pseudo-corrected features, and the standardization of such features. Because it is written in Aramaic-Hebrew script, it may reveal substandard phonetic, morphologic, lexical and syntactic features, unlike the conventional and strictly established Arabic orthography. This becomes especially evident in cases of close phonetic spelling, which is also the case for the present material.