Ladino, otherwise known as Judeo-Spanish, is the spoken and written Hispanic language of Jews of Spanish origin. Ladino did not become a specifically Jewish language until after the expulsion from Spain in 1492 - it was merely the language of their province. It is also known as Judezmo, Dzhudezmo, or Spaniolit.
When the Jews were expelled from Spain and Portugal they were cut off from the further development of the language, but they continued to speak it in the communities and countries to which they emigrated. Ladino therefore reflects the grammar and vocabulary of 14th and 15th century Spanish. The further away from Spain the emigrants went, the more cut off they were from developments in the language, and the more Ladino began to diverge from mainstream Castilian Spanish.
In Amsterdam, England and Italy, those Jews who continued to speak 'Ladino' were in constant contact with Spain and therefore they basically continued to speak the Castilian Spanish of the time. However, in the Sephardi communities of the Ottoman Empire, the language not only retained the older forms of Spanish, but borrowed so many words from Hebrew, Arabic, Greek, Turkish, and even French, that it became more and more distorted. Ladino was nowhere near as diverse as the various forms of Yiddish, but there were still two different dialects, which corresponded to the different origins of the speakers.
'Oriental' Ladino was spoken in Turkey and Rhodes and reflected Castilian Spanish, whereas 'Western' Ladino was spoken in Greece, Macedonia, Bosnia, Serbia and Romania, and preserved the characteristics of northern Spanish and Portuguese. The vocabulary of Ladino includes hundreds of archaic Spanish words which have disappeared from modern day Spanish, and also includes many words from different languages that have been substituted for the original Spanish word, from the various places Ladino speaking Jews settled.
Assimilation to the languages of the majority populations whittled away at the Ladino communities of Europe and North Africa a fair bit in the first part of the 20th century, the mass emigration of the Sephardim to western Europe and points overseas did more, and the Holocaust decimated many communities, including the Jewish plurality population in the Greek city now known as Thessaloniki. The modern Ladino language is the most vibrant of the Judeo-Romance languages, and most Ladino speakers now live in Israel. Alas, Israel's Ladino-speaking community is quick succumbing to assimilation into a much larger Hebrew-speaking population. No, there do not seem to be many prospects for a revival like Yiddish, since Yiddish at its peak commanded an audience of millions and still has a certain vitality to it as a living language. More's the pity, but the last remnants of Jewish Spain are being documented.