>>Then I remembered that by the fifteen century the Jews were expelled from Spain<<

Not quite right, juanmaria - the Jews expelled from Spain would have spoken a language that had its origins in the Latin languages, and not Germanic/Polish, from which Yiddish derives.

The "Sephardi" (Latin) Jews are a different group from the "Ashkenazi" (Middle and Eastern European). Their practises, liturgy, and even foods are influenced by their respective regions. In addition, spoken Hebrew, the language of prayer, is clearly distinguishable between the groupings.

Many Sephardi Jews speak Esperanto, or Ladino, as well as English and/or French. Very few of them (if any) use Yiddish.

I've gone off-topic again!