In Yiddish, about half the "ei" words are pronounced the same as German (mein, sein, drei...) but the others shift to an "ey" sound (rhymes with "day"): éins, zwéi, kléin… We had a discussion here (Why is "Zeile" but not "Zeiger" differently pronounced in the south?) a couple of years ago that seemed to indicate some parallels in a south German dialect, but we never got to the bottom of it. I wonder if someone has some ideas as to what is going on here?

Some of the other words that shift are béin, fléisch, wéiss (to know), kéit; and others that stay the same as German are weiss (the color), frei, bleiben, steigen. Any ideas?

  • I associate similar sound shifts with some eastern dialects (Böhmisch, Schlesisch) and Berlinerisch ("Oogen, Fleesch und Beene"). But these are anecdotal impressions and may be wrong. Wikipedia (de.wikipedia.org/wiki/Jiddisch#Phonetik) associates the sounds shifts in Yiddish with Mitteldeutschen Dialekten, so the southern German parallels may be a red herring. Perhaps if you look more closely at the sound shifts between Althochdeutsch and the various German dialects you might find some clues about what is going on exactly.
    – dirkt
    Commented Jun 19, 2014 at 8:23

1 Answer 1


What you observed here is a change in the diphthongization which took place from the 12. Century in the transition from Middle High German to New High German.

Amongst other phenomena the diphthong 'ei' changed it's pronunciation from [ɛɪ] to [aɪ]. This took place gradually, moving from Bavarian regions to the north. Some dialects, and Yiddish, did not or only partly accept this.

Interestingly the spelling of these diphthongs only rarely followed the change in pronunciation (e.g. Keiser > Kaiser, Leib > Laib).

  • Nice. I wonder if any other dialects retain some of the same pronunciation patterns as Yiddish? Commented Jun 19, 2014 at 16:10
  • 3
    More interestingly and thanks to loan words from English and French, <ai> is now the most prevalent grapheme sequence corresponding to /ɛɪ/, e.g. Trainer, Mail. It’s almost exclusively used in xenisms and for disambiguation of homophones like /laɪp/. The rest are very infrequent words.
    – Crissov
    Commented Jun 20, 2014 at 14:28
  • @Crissov: never thought of this, but that's interesting indeed :)
    – Takkat
    Commented Jun 20, 2014 at 19:19
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    Not all diphtongs are the result of a diphtongization. The Diphtong in Kaiser probably predates diphtongization because it was borrowed from Latin Caesar when ae still was a diphtong.
    – RHa
    Commented Apr 9, 2018 at 6:51
  • According etymonline.com, Laib originates from Proto-German *khlaibuz, so the diphtong was already there before diphtongization.
    – RHa
    Commented Apr 9, 2018 at 6:58

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