But 'ae' isn't a monophthong in 'aeroplane', is it? So what can you mean by this?There is a very good caſe to be made for pronouncing 'æ' as in 'æroplane', on the aſſumption that the change in ſpelling from 'AI' to 'Æ' at the beginning of the claſſical period reflected the collapse of the original diphthong into a monophthong intermediate between 'A' and 'E'.
Perhaps to distinguish it from the āī.Why elſe would the ſpelling have changed in favour of a form more cumberſome to write?
A ſingle, ſimple vowel without any glide, ſimilar in poſition to the ſhort 'a' in 'hat', but with more ſtreſs, and longer duration, indeed with about the ſame value to that for which the 'æ' character was borrow'd for uſe in writing Anglo Saxon. Being a long, and likely ſomewhat tense vowel, it would have been very easy for 'æ' to cloſe to 'e:' in moſt Mediæval pronunciations of Latin.But 'ae' isn't a monophthong in 'aeroplane', is it? So what can you mean by this?