In Yiddish, the diphthongization applied not only to MHG long vowels but also to /ɛː oː/ in words of Hebrew (in stressed open syllables) or Slavic origin: Vowel breaking is present in Scottish Gaelic with the following changes occurring often but variably between dialects: Archaic Irish eː → Scottish Gaelic iə and Archaic Irish oː → Scottish Gaelic uə [7] Specifically, central dialects have more vowel breaking than others.
The middle vowel was subsequently lost if a triphthong was produced: Modern Catalan cuixa, vuit, llit (cf.
The result of breaking varies between languages: e and o became ie and ue in Spanish, ie and uo in Italian and ie and eu /ø/ in French.
In Quebec French, long vowels are generally diphthongized when followed by a consonant in the same syllable (even when a final [ʁ] is optionally made silent).
Some scholars[8] believe that Proto-Indo-European (PIE) i, u had vowel-breaking before an original laryngeal in Greek, Armenian and Tocharian but that the other Indo-European languages kept the monophthongs: However, the hypothesis has not been widely adopted.
In Minangkabau, the Proto-Malayic vowels *i and *u are broken to ia and ua before word-final *h, *k, *l, *ŋ, *r (*təlur > *təluar > talua "egg").
[9] In Rejang, the Proto-Malayo-Polynesian vowels *ə, i, and u are broken to êa, ea, and oa before any of word-final consonants above except *k and *ŋ (*tənur > *tənoar > tênoa "egg").
[10] This process has been transphonologized by loss of *l and *r and merging of several word-final consonants into a glottal stop (*p, *t, *k in Minangkabau, or *k, *h in most dialects of Rejang except Kebanagung).
[10] Although Acehnese is also spoken in Sumatra, the entire Chamic family has undergone vowel breaking separately.