For a lexicon that's supposedly dead, Yiddish language and culture are undergoing a remarkable revival.
Klezmer music, with its signature laughing/weeping clarinet and violin, is enjoying a worldwide resurgence, even in Warsaw, Poland, where almost no Jews are left. The Yiddish Book Center in Amherst, Mass., is translating and digitizing a million rescued volumes and organizing Yidstock, an annual festival of new Yiddish music. Researchers are learning the language in order to understand historical records. Israeli universities have established Yiddish language and literature centers, often attended by non-Jewish students from Germany and other Holocaust-linked countries.
And, no, Yiddish is not a German dialect , unless you also consider English a German dialect. But don't take my word for it:
The basic grammar and vocabulary of Yiddish, which is written in the Hebrew alphabet, is Germanic. Yiddish, however, is not a dialect of German but a complete language—one of a family of Western Germanic languages, that includes English, Dutch, and Afrikaans. Yiddish words often have meanings that are different from similar words in German.