The Judeo-Arabic languages are a group of languages spoken by Jews of ethnic Arabic origin. These are often considered dialects of Arabic, though they contain borrowings from Hebrew and Aramaic. There are three script usages for writing the Judeo-Arabic languages; phonetic, Hebraicized, and Arabicized. All three use Hebrew letters or modifications of Hebrew letters.
Phonetic orthography was only used for writing early Judeo-Arabic texts, alongside Arabicized orthography, which suddenly replaced it in the 10th century. Arabicized orthography uses Hebrew-based letters but applies Classical Arabic spelling conventions to the writing. Long vowels and short consonants are written with full letters; short vowels and long consonants are written with diacritics. Arabic diacritic dots are also used to modify some consonant letters to enable Judeo-Arabic sounds not present in spoken Hebrew to be represented.
Hebraicized orthography is in some ways a combination of the previous two styles. Since the 15th century it has been used alongside Arabicized orthography, from which some influence is apparent. However, it displays much greater influence from Hebrew and Aramaic spelling, and uses diacritics to represent short vowels, resulting in a more phonetic representation than was possible with Arabic spelling conventions.
Benjamin Hary "Adaptations of the Hebrew Script" pp727-734 The World's Writing Systems