This principle of semantic nonequivalence extends to optional allomorphs [...]. For example, the alternant pronunciations of 'duty' (1) /duwtiy/ and (2) /dyuwtiy/ carry certain distinct connotations. In some circumstances the form /dyuwtiy/ induces an unfavorable responce from the listener, who interprets it as pedantic or associated with people whose culture he does not appreciate. On the other hand, among a certain small set of speakers of American English the form /duwtiy/ is a mark of educational and cultural inferiority.
- Nida (1949), a pag.151