The open-mid central unrounded vowel, or low-mid central unrounded vowel, is a type of vowel sound, used in some spokenlanguages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ɜ⟩. The IPA symbol is not the digit ⟨3⟩ or the Cyrillic small letter Ze (з; the latter arose from the Greek letter zeta, Ζ ζ). The symbol is instead a reversed Latinized variant of the lowercase epsilon, ɛ. The value was specified only in 1993; until then, it had been transcribed ⟨ɛ̈⟩.
The IPA prefers terms "close" and "open" for vowels, and the name of the article follows this. However, a large number of linguists, perhaps a majority, prefer the terms "high" and "low".
Sulcalized (the tongue is grooved like in [ɹ]). 'Upper Crust RP' speakers pronounce a more open vowel [ɐː], but for most other speakers it's actually mid ([ɜ̝ː]). This vowel corresponds to rhotacized[ɝ] in rhotic dialects.
Thomas, Erik R. (2001), An acoustic analysis of vowel variation in New World English, Publication of the American Dialect Society, 85, Duke University Press for the American Dialect Society, ISSN0002-8207