There are a number of theories regarding the etymology of the word. The best known is that it originates from the cultural differences in dress that developed between the more westernized Western European Jews who wore shorter "jackets" ("yekke", cf. German Jacke with an initial y-sound instead of the English j-sound) from the traditional longer coats while the outer clothing worn by the Eastern European Jews was typically longer.
Another theory is that the word derives from "Yekkef", the Western European pronunciation of the name "Jacob" or "Jack", which differs from the Eastern European pronunciation, "Yankef" or "Yankev" (also see German Jäckel, pronounced "yekkel", the German diminutive form of Jakob).
Furthermore, since Yiddish is derived from Middle High German, German sources occasionally note that Yiddish yekk(e) is largely homophone with jeck(e), the Rhenish dialectal form of Standard German Geck of uncertain origin but in contexts relating German jeck(e) to Yiddish yekk(e) attributed to patriarch Jacob in the Bible as does above-mentioned Yekkef theory.
Rhenish Jeck(e) as a noun denotes a "fool", "jester", or "crazy person" (both in a general sense, and in particular in association with the Rhenish carnival where the term describes a traditional folkloric stage figure akin to the Italian harlequin as well as merely a reveler celebrating the carnival season in a "foolish" manner due to ebriety) and as an adjective means "crazy", "mad", "insane", whereas the dated High German word Geck originally meant a "fool" as well but later transformed to particularly signify a "dandy" or "fop".
However, the broader usage of the Rhenish noun Jeck(e) in the Rhineland area has given the term a general meaning resembling "person", "(mere) mortal", or "humble sinner" with a particularly (self-)ironic connotation, such as in the common saying Jeder Jeck is anders (lit. "Every fool is different", with an idiomatic meaning of "Different strokes for different folks" or "Live and let live"). From there, a transformation into an ethnonym such as for Jewish people would be akin to the fate of similar terms such as Germanic man (word) and *þiuda-, and the equivalent words for "person" or "human being" in many other languages around the world.
The term is often used in a slightly derogatory or cynical manner, although it is also used as a compliment. It is used mainly in reference to the German Jews’ legendary attention to detail and punctuality. This sense for detail extends into the strict adherence to minhagim (religious customs, especially when pertaining to the synagogue service). Oberlanders — Jews originating from the northwestern part of the former Kingdom of Hungary — are often confused with yekkes due to similar minhagim.
The wave of immigration to British Mandated Palestine in the 1930s and 1940s known as the Fifth Aliyah was composed predominantly of Yekkes. Many of them settled in the vicinity of Ben Yehuda Street in Tel Aviv, leading to the nickname "Ben Yehuda Strasse." Their struggle to master Hebrew produced a dialect known as "Yekkish." The Ben Yehuda Strasse Dictionary: A Dictionary of Spoken Yekkish in the Land of Israel, published in 2012, documents this language.
Today, because of the Holocaust, very few original Yekkes are still German residents, but they remain in regions such as Switzerland, Eastern France (Alsace and Lorraine), Netherlands and Luxembourg. A significant community escaped Frankfurt after Kristallnacht, and relocated to the Washington Heights region of New York City, where they still have a synagogue, K'hal Adass Jeshurun, which punctiliously adheres to the Yekkish liturgical text, rituals, and melodies.
A group of Yekkes established kibbutz Chofetz Chaim in the Gedarim region of Israel just south of Tel Aviv. Recently a few new Yekkish communities have been started in Israel by "Machon Moreshet Ashkenaz," and one of the leading communities is K'hal Adas Yeshurun of Jerusalem, which is running a "Nusach Project", a project of preserving the special Yekkish melodies.
The short film Chaja & Mimi focuses on the ambivalent relationship of two Yekkish Israeli women to the city of their birth, Berlin.
- Weinbaum, Laurence; McPherson, Colin (2000). "No Milk and No Honey: The Yekkes and the Ostjuden". Jewish Quarterly. 47 (3): 25–30. doi:10.1080/0449010X.2000.10705191 (inactive 29 November 2019).
- The American Yekkes (Yisrael Kashkin, 2016)