/ɚ/ in American (including Canadian) English as in “nurse”, “curd”, “certain”, is usually labelled a “rhotacized vowel” in a phonemic context but it’s more precisely described as an approximant (due to the fact that it has some constriction around the palato-velar area, uvula, glottis, molars, and/or labio-dental area, depending on which variety you speak). And as I said, “full” is pronounced with no vowel in certain varieties.
In these examples such as curd and full, isn’t shwa the vowel? You can’t actually not have a vowel if you pronounce it.
/ɚ/ in American (including Canadian) English as in “nurse”, “curd”, “certain”, is usually labelled a “rhotacized vowel” in a phonemic context but it’s more precisely described as an approximant (due to the fact that it has some constriction around the palato-velar area, uvula, glottis, molars, and/or labio-dental area, depending on which variety you speak). And as I said, “full” is pronounced with no vowel in certain varieties.