Yiddish phonology

There is significant phonological variation among the various Yiddish dialects. The description that follows is of a modern Standard Yiddish that was devised during the early 20th century and is frequently encountered in pedagogical contexts.

Consonants

 * are bilabial, whereas are labiodental.
 * The contrast has collapsed in some speakers.
 * The palatalized coronals appear only in Slavic loanwords. The phonemic status of these palatalised consonants, as well as any other affricates, is unclear.
 * and are velar, whereas  are palatal.
 * is an allophone of after, and it can only be syllabic.
 * is an allophone of before.
 * The phonetic realization of and  is unclear:
 * In the case of, puts it in the "velar" column, but consistently uses a symbol denoting a voiceless uvular fricative ⟨χ⟩ to transcribe it. It is thus safe to assume that  is phonetically uvular.
 * In the case of, puts it in the "palatalized" column. This can mean that it is either palatalized alveolar  or alveolo-palatal .  may actually also be alveolo-palatal , rather than just palatal.
 * The rhotic can be either alveolar or uvular, either a trill  or, more commonly, a flap/tap.
 * The glottal stop appears only as an intervocalic separator.

As in the Slavic languages with which Yiddish was long in contact (Russian, Belarusian, Polish, and Ukrainian), but unlike German, voiceless stops have little to no aspiration; unlike many such languages, voiced stops are not devoiced in final position. Moreover, Yiddish has regressive voicing assimilation, so that, for example, זאָגט ('says') is pronounced  and הקדמה  ('foreword') is pronounced.

Vowels
The vowel phonemes of Standard Yiddish are:


 * are typically near-close respectively, but the height of  may vary freely between a higher and lower allophone.
 * appears only in unstressed syllables.


 * The last two diphthongs may be realized as and, respectively.

In addition, the sonorants and  can function as syllable nuclei:
 * אײזל  'donkey'
 * אָװנט  'evening'

and appear as syllable nuclei as well, but only as allophones of, after bilabial consonants and dorsal consonants, respectively.

The syllabic sonorants are always unstressed.

Dialectal variation
Stressed vowels in the Yiddish dialects may be understood by considering their common origins in the Proto-Yiddish sound system. Yiddish linguistic scholarship uses a system developed by Max Weinreich in 1960 to indicate the descendent diaphonemes of the Proto-Yiddish stressed vowels.

Each Proto-Yiddish vowel is given a unique two-digit identifier, and its reflexes use it as a subscript, for example Southeastern o11 is the vowel /o/, descended from Proto-Yiddish */a/. The first digit indicates Proto-Yiddish quality (1-=*[a], 2-=*[e], 3-=*[i], 4-=*[o], 5-=*[u]), and the second refers to quantity or diphthongization (−1=short, −2=long, −3=short but lengthened early in the history of Yiddish, −4=diphthong, −5=special length occurring only in Proto-Yiddish vowel 25).

Vowels 23, 33, 43 and 53 have the same reflexes as 22, 32, 42 and 52 in all Yiddish dialects, but they developed distinct values in Middle High German; Katz (1987) argues that they should be collapsed with the −2 series, leaving only 13 in the −3 series.

Comparison with German
In vocabulary of Germanic origin, the differences between Standard German and Yiddish pronunciation are mainly in the vowels and diphthongs. All varieties of Yiddish lack the German front rounded vowels and, having merged them with  and , respectively.

Diphthongs have also undergone divergent developments in German and Yiddish. Where Standard German has merged the Middle High German diphthong ei and long vowel î to, Yiddish has maintained the distinction between them; and likewise, the Standard German corresponds to both the MHG diphthong öu and the long vowel iu, which in Yiddish have merged with their unrounded counterparts ei and î, respectively. Lastly, the Standard German corresponds to both the MHG diphthong ou and the long vowel û, but in Yiddish, they have not merged. Although Standard Yiddish does not distinguish between those two diphthongs and renders both as, the distinction becomes apparent when the two diphthongs undergo Germanic umlaut, such as in forming plurals:

The vowel length distinctions of German do not exist in the Northeastern (Lithuanian) varieties of Yiddish, which form the phonetic basis for Standard Yiddish. In those varieties, the vowel qualities in most long/short vowel pairs diverged and so the phonemic distinction has remained.

Yiddish has some coincidental resemblances to Dutch in vowel phonology, which extend even to orthography, such as Dutch ij versus Yiddish tsvey judn, both pronounced /ɛɪ/; and Dutch ui (pronounced /œy/) versus Yiddish vov yud (/ɔj/). For example, the Yiddish "to be" is זיין, which orthographically matches Dutch zijn more than German sein, or Yiddish הויז, "house", versus Dutch huis (plural huizen). Along with the pronunciation of Dutch g as /ɣ/, Yiddish is said to sound closer to Dutch than to German because of that even though its structure is closer to High German.

There are consonantal differences between German and Yiddish. Yiddish deaffricates the Middle High German voiceless labiodental affricate to  initially (as in פֿונט funt, but this pronunciation is also quasi-standard throughout northern and central Germany); /pf/ surfaces as an unshifted  medially or finally (as in עפּל  and קאָפּ ). Additionally, final voiced stops appear in Standard Yiddish but not Northern Standard German.

Comparison with Hebrew
The pronunciation of vowels in Yiddish words of Hebrew origin is similar to Ashkenazi Hebrew but not identical. The most prominent difference is kamatz gadol in closed syllables being pronounced same as patah in Yiddish but the same as any other kamatz in Ashkenazi Hebrew. Also, Hebrew features no reduction of unstressed vowels and so the given name Jochebed יוֹכֶבֶֿד would be in Ashkenazi Hebrew but  in Standard Yiddish.

Patah in open syllable, as well as hataf patah, are unpredictably split between A1 and A2: קַדַּחַת, נַחַת ; חֲלוֹם, חֲתֻנָּה.