意第绪语（ייִדיש yidiš，又译「依地语」）属于日耳曼语族。全球大约有三百万人在使用，大部分的用户是犹太人，而且其中主要是阿什肯纳兹犹太人在操用此语。意第绪（语）这个称呼本身可以来代表“犹太人”（跟德语的“犹第绪”一词来比较），也可能是“意第绪-塔乌特绪”（ייִדיש־טײַטש）的简称，或者说是用作表示“德国犹太人”的称呼。在“意第绪（语）”称呼于13至14世纪的早年发展阶段，它也是被当作“德国犹太人”的意思；在早先时期有时候“意第绪”，亦如它以后所表示的意思，也被视“意第绪语”为这种语言的名称来看待。

Yiddish (ייִדיש, יידיש or אידיש, yidish/idish, literally "Jewish"; in older sources ייִדיש-טײַטש "Yiddish-Taitsh" (English: Judaeo-German)) is the historical language of the Ashkenazi Jews. It originated during the 9th century in Central Europe, providing the nascent Ashkenazi community with an extensive Germanic based vernacular fused with elements taken from Hebrew and Aramaic, as well as from Slavic languages and traces of Romance languages. Yiddish is written with a fully vocalized alphabet based on the Hebrew script.