Like Old Spanish, Judaeo-Spanish keeps the /S/ and /Z/ palatal phonemes, both changed to /x/ in modern Spanish. But unlike Old Spanish, Judaeo-Spanish has an /x/ phoneme taken over from Hebrew.
Until recent times, the language was widely spoken throughout the Balkans, Turkey, the Middle East, and North Africa, having been brought there by Jewish refugees fleeing Spain following the expulsion of the Jews in 1492. It was the most used language in Salonica. Over time, a corpus of literature, both liturgical and secular, developed.
During the Jewish Enlightenment, as Sephardim in the Ottoman Empire studied in schools of the Alliance Israelite Universelle, Judaeo-Spanish drew from French for neologisms.
In the twentieth century, the number of speakers declined sharply: entire communities were eradicated in the Holocaust, while the remaining speakers, most of whom migrated to Israel, adopted Hebrew. At the same time, it arose the interest of philologists since it conserved language and literature previous to the standardizing of Spanish.
Most native speakers today are elderly immigrants, who have not transmitted the language to their children or grandchildren. In addition, Sephardic communities in several Latin American countries still use Ladino.
Here is a sample:
Non komo muestro Dio,
Non komo muestro Sinyor,
Non komo muestro Rey,
Non komo muestro Salvador.
It is also sung in Hebrew (Ein k'Eloheynu) but the tune is different.