For me, these are normally monophthongs unless followed by another vowel or, when I am approximating General American, word-final, where then they may be diphthongs, but only are so very inconsistently. I tend to prefer to analyze my dialect as having these as monophthongs, with cases in which they have glides synchronically being cases of optional epenthesis, especially since how frequently these glides appear depends heavily on not only register but also which vowel follows them.Nancy Blackett wrote:I prefer to use /e/ and /o/, mainly for notational convenience; for me they vary between pure vowels and diphthongs, and not always predictably. I would find it strange to refer to weather [veinz], but the blood vessels can be either [venz] or [veinz]. There are historical reasons for this, but I have no idea why they should have affected my own idiolect.Travis B. wrote:In North American English contexts, I still see these not infrequently referred to as /e/ and /o/ rather than /eɪ̯/ and /oʊ̯/, even though I would say that the latter pair are more correct for speaking about NAE as a whole.Rory wrote:A finlay points out, this is how I talk. fate and boat are roughly [fet], [bot]. This doesn't change the fact that for General American, these vowels are transcribed as /eɪ/ and /oʊ/.Travis B. wrote:One should remember that quite a few English varieties do normally have monophthongs for historical /eɪ̯/ and/or /oʊ̯/, which consequently are often marked as simply /e/ and /o/ respectively. Also, at least in General American (aside from more progressive varieties thereof that have lost historical vowel length) and Received Pronunciation, /ɑː/ is indeed long and not short.
However, for speaking about North American English as a whole, I still prefer to speak of /eɪ̯/ and /oʊ̯/ rather than /e/ and /o/, no matter how I analyze my own dialect, due to this being more diachronically correct and broadly applicable. Even in my own dialect, the monophthongs I have therefor are almost certainly descended from a historical /eɪ̯/ and /oʊ̯/, with the cases where I do have off-glides diachronically not being cases where glides were inserted but rather cases where glides were not lost*.
* This is especially since I have certain words such as cooperate [kʰəːˈwapʁ̩ˤːʁˤeʔ] (1) where the offglide was preserved as a distinct segment /j/ or /w/, and not subject to further reduction of the /eɪ̯/ and /oʊ̯/ from which they originated.
(1) X-SAMPA: [k_h@:"wapR=_?\:R_?\e?]