Prerhotic

While /ɛ/ and /ɪ/ lost their distinctiveness in pre-rhotic, tautosyllabic positions, the basic distinction back ~ front was maintained in forms such as the following: fern [fɛɹn], General IrE [fərn]; turn [tʌɹn], General IrE [tərn].

1993 Summer, Ralph H. Emerson, “The Distribution of Eighteenth-Century Prerhotic O-Phonemes in Walker’s Critical Pronouncing Dictionary” in American Speech LXVIII, № 2, pages 115–138

We turn now to the prerhotic context in (15)–(17).