Close-mid central unrounded vowel Close-mid central unrounded vowel The close-mid central unrounded vowel, or high-mid central unrounded vowel, is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is . This is a mirrored letter e, and should not be confused with the schwa , which is a turned e. It was added to the IPA in 1993; before that, this vowel was transcribed (Latin small letter e with umlaut, not Cyrillic small letter yo). Certain older sources transcribe this vowel . The letter may be used with a lowering diacritic ,
Vowel length table below: Vowel length may often be traced to assimilation. In Australian English, the second element of a diphthong has assimilated to the preceding vowel, giving the pronunciation of "bared" as , creating a contrast with the short vowel in "bed" . Another common source is the vocalization of a consonant such as the voiced velar fricative or voiced palatal fricative, e.g. Finnish illative case, or even an approximant, as the English 'r'. A historically-important example is the laryngeal theory, which states that long vowels in the Indo-European languages were formed from short vowels, followed by any one of the