Its vowel backness is back, which means the tongue is positioned back in the mouth without creating a constriction that would be classified as a consonant. Unrounded back vowels tend to be centralized, which means that often they are in fact near-back.
It is unrounded, which means that the lips are not rounded.
Before World War II, the /ʌ/ of Received Pronunciation was phonetically close to a back vowel [ʌ], which has since shifted forward towards [ɐ] (a near-open central unrounded vowel). Daniel Jones reported his speech (southern British) as having an advanced back vowel [ʌ̟] between his central /ə/ and back /ɔ/; however, he also reported that other southern speakers had a lower and even more advanced vowel that approached cardinal [a]. In American English varieties, such as in the West, the Midwest, and the urban South, the typical phonetic realization of the phoneme /ʌ/ is an open-mid central [ɜ]. Truly backed variants of /ʌ/ that are phonetically [ʌ] can occur in Inland Northern American English, Newfoundland English, Philadelphia English, some of African-American English, and (old-fashioned) white Southern American English in coastal plain and Piedmont areas. However, the letter ⟨ʌ⟩ is still commonly used to indicate this phoneme, even in the more common varieties with central variants [ɐ] or [ɜ]. That may be because of both tradition and some other dialects retaining the older pronunciation.
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