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 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⟩.
Conversely, ⟨ə⟩, the symbol for the mid central vowel may be used with a lowering diacritic ⟨ə̞⟩ to denote the open-mid central unrounded vowel, although that is more accurately written with an additional unrounding diacritic ⟨ə̞͑⟩ to explicitly denote the lack of rounding (the canonical value of IPA ⟨ə⟩ is undefined for rounding).
Sulcalized (the tongue is grooved like in [ɹ]). "Upper Crust RP" speakers pronounce a more open vowel [ɐː], but for most other speakers it is actually mid ([ɜ̝ː]). This vowel corresponds to rhotacized[ɝ] in rhotic dialects.
Gordon, Matthew (2004b), "The West and Midwest: phonology", in Kortmann, Bernd; Schneider, Edgar W. (eds.), A Handbook of Varieties of English: Volume 1: Phonology, Walter de Gruyter, p. 340, ISBN3-11-017532-0
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
Tillery, Jan; Bailey, Guy (2004), "The urban South: phonology", in Kortmann, Bernd; Schneider, Edgar W. (eds.), A Handbook of Varieties of English: Volume 1: Phonology, Walter de Gruyter, p. 333, ISBN3-11-017532-0