Uriel Weinreich was one of the top scholars of the Yiddish language, and to a lesser degree, of Yiddishkeit. He was nonetheless overshadowed by his father, the great Max Weinreich, who wrote a four volume history of the language (in Yiddish, with a one-volume English abridgement) and who started the massive Yiddish-Yiddish dictionary (under the aegis of Columbia University, I think) which is still "under construction".
There aren't many good Yiddish-English dictionaries out there. Uriel Weinreich's is one of the two I'm familiar with, the other being Alexander Harkavy's Yiddish-English-Hebrew Dictionary.
Weinreich gives good grammatical information in his entries, such as verb aspect and case of verb object, along with unpredictable forms such as the past participle. Both alphabets are very clear and distinct, and big enough to be readable for those past the bloom of youth. The English-Yiddish section is valuable for those using the book in Yiddish classes and for those who would like to speak, as well as read, Yiddish. Of course, it decreases the overall size of the dictionary, so a lot of the words you encounter won't show up in it.
The big drawback is the work's prescriptive nature, meaning that this is how Weinreich thought Yiddish *should* be spoken and written, not how it *was* spoken and written. Critics such as Solomon Birnbaum have even claimed that Weinreich made words up, if he didn't find them ready to hand. True, new words are formed or borrowed all the time, but that's the job of writers, subject specialists, members of subcultures, teenagers, grannies, and just about everybody *but* lexicographers.
Further, if your goal is to read classic Yiddish literature (Perets, Sholom Aleichem, Yitskhak Manger etc.), this is not the book for you. I would recommend Harkavy's dictionary, if you can find it. He doesn't give the noun genders, there is little grammatical guidance and the print is hard to read, but the word you're looking for is likely to be there. And the book's very age (1920? or somewhere along there) is a plus, for this purpose. Of course, any serious student of Yiddish needs to keep good Polish, Hebrew and other dictionaries on hand, otherwise many words will remain a mystery, whatever Yiddish dictionary is used.
***Note (April 2013)***
I need to:
a) update this review a bit:
In addition to Harkavy's Dictionary, any reader of Yiddish literature would want to consider the recent
Arumnemik Yidish-English verterbukh /
Solon Beinfeld; Harry Bochner
xxxix, 704 p. ; 27 cm.
Bloomington, Ind. : Indiana University Press, ; ISBN: 9780253009838 0253009839
It is an adaptation of a French original. I'm not as familiar with it as I would like to be yet, but coverage is comparable to Harkavy's, though it lacks the patina of Old (American) Yiddishkeit that the older work has,
b) offer a correction:
though I did not in anyway overrate the elder Weinreikh's stature, the great multivolume work I had in mind was actually the work, principally, of Yudel Mark and Yehuda Yofe:
Groyser verterbukh fun der Yidisher shprakh /
Judah Achilles Joffe; Yudel Mark
v. : ill. ; 27 cm.
whereas the dictionary associated with the elder Weinreikh is:
Der oytser fun der Yidisher shprakh /
Nahum Stutchkoff; Max Weinreich
lvi, 933 p. ; 27 cm.
[New York] : Yidisher Visnshaftlekher Institut