Yiddish language
This tongue is a chief vernacular of Ashkenazic Jews, who are native to, or who have antecedents in, eastern and central Europe. Though it is one of the Germanic languages, Yiddish is written in Hebrew characters (some of them used differently than for writing Hebrew). Yiddish (meaning "Jewish") arose between the 9th and 12th centuries in southwestern Germany as an adaptation of Middle High German dialects to the special needs of Jews. To the original German were added those Hebrew words that pertained to Jewish religious life. Later, when the bulk of European Jewry moved eastward into areas occupied predominantly by Slavic-speaking peoples, some Slavic influences were acquired. The vocabulary of the Yiddish spoken in eastern Europe during recent times comprised about 85 percent German, 10 percent Hebrew, and 5 percent Slavic, with traces of Romanian, French, and other elements. Many English words and phrases entered Yiddish, becoming an integral part of the language as it is spoken in the U.S. and other English-speaking countries. Apart from vocabulary changes, modern Yiddish differs from modern German mainly in the simplification of inflections and syntax, the acquisition of a few grammatical traits influenced by Slavic speech, and its looser pronunciation of Germanic words. Yiddish pronunciation was also significantly influenced by Slavic languages. In its word formation and use of auxiliary verbs Yiddish is similar to English, which also is a Germanic language with a simplified grammar and a variously enriched vocabulary.

Yiddish exists in two groups of dialects, one of which is further subdivided. The western dialect, with few speakers, is centered in German-speaking areas of western Europe. The more widely distributed eastern group has a northeastern branch and a southern branch. The northeastern branch includes the Yiddish spoken in the Baltic countries and in the northwestern areas of Russia, and by Jewish immigrants or descendants from those areas. The southern branch-which has central and southeastern subgroups-includes the dialects spoken in Poland, Romania, and Ukraine.

Yiddish is a highly plastic and assimilative language, rich in idioms, and possessing remarkable freshness, pithiness, and pungency. Since it was spoken by ordinary people rather than by scholars, its vocabulary is weak in abstractions. By the same token it has few items descriptive of nature, with which the Jews of eastern Europe had relatively little contact, and a wealth of words and expressions descriptive of character and of relations among people. It makes liberal use of diminutives and terms of endearment and exhibits a variety of expletives. The use of proverbs and proverbial expressions is considerable. These qualities and usages give Yiddish a uniquely warm and personal flavor.

In the early years of the 20th century Yiddish was spoken by an estimated 11 million people living mainly in eastern Europe and the U.S. The use of the language has been declining since then. The initial cause was the extermination of the Jewish communities in Poland and other eastern European countries during World War II. An important factor that also contributed to the decline in usage was the adaptation by Jews to the languages predominant in the United States and in the Soviet Union. In 1984, however, a Russian-Yiddish dictionary containing essays on etymology and grammar was published in the USSR; since then a few novels by Russian Jews have been written in Yiddish. In Israel the Hebrew language is predominant, and Yiddish is a second language, cultivated largely by members of the older generation who have an eastern European background; only a few modern Israeli poets write in Yiddish. In an effort to ensure its preservation, the Hebrew University of Jerusalem teaches Yiddish, as do certain American schools and colleges. The YIVO Institute for Jewish Research, founded in Poland at the turn of the century and moved to New York City in 1940, includes the study of the development of the Yiddish language as part of its effort to preserve the history of Eastern European shtetl, or village, culture.