Petri Hispani De lingua arabica libri duo (1883)
P. Alcala, P. Lagarde / Goettingen / 1883 (1505) /pages: 467 / djvu 20MB
Contains two famous works on spoken Arabic, originally published in 1505, after the fall of Granada: Vocabulista arabigo en letra castellana and Arte para ligerament saber la lengua Arauiga (spellings vary as always for books from that time).
The scan quality could be better, but this is a very important historical document. As indicated by its title, it contains a short grammar with some sentences intended for checking the religious indoctrination of the interlocutor and a vocabulary list.
As with similar works on Nahuatl and Quechua, the better your Spanish is, the easier this read will be.