To my understanding, most American and British English dialects[0] have /eɪ/, e.g. in "maze", which I imagine is quite close to /ɛi/.
[0] The exceptions being dialects where it monophthongizes to /eː/
[0] The exceptions being dialects where it monophthongizes to /eː/
Phonemes are a funny thing: if an American were to pronounce that last name perfectly (or a Dutch person speaking English, for that matter), other Americans would still hear /daɪkstɹə/, or at most, "/daɪkstɹə/ but it sounds a bit foreign".
Some sounds which we don't produce are audibly not-English-phonemes, like German ü or Scandanavian ø, but others are not. Another example of this is that native English speakers aren't usually sensitive to the difference between the r sound in our word "pear" and the r sound in Spanish "pero", but recognize that "perro" is a different rhotic sound.
If I may ask purely out of curiosity, are you a native English speaker? I only say this because, to my American English ear, [eɪ] and [ɛi] are virtually indistinguishable. Maybe I'm just misunderstanding what you're trying to say....
I encourage you to listen to a native Dutch speaker pronounce Mynheer Dijkstra's name, which you can do on Wikipedia: https://en.wikipedia.org/wiki/Edsger_W._Dijkstra
Does that sound more like "dike" or more like "day"? To me (yes, native American English speaker, of one of the dialects very close to 'Standard'), it is obviously more like the former.
I might've figured out the disconnect. According to this image on Wikipedia[0], the Northern Standard Dutch realization of [ɛi] starts lower than the monophthongal [ɛ] in the same dialect[1]. Just speculation on my part, but maybe in the context of Dutch linguistics, [ɛi] conventionally signifies a wider diphthong than I would've naïvely thought? (If so, I guess this makes me a cautionary tale against directly comparing IPA transcriptions between languages....)
[0] https://en.wikipedia.org/wiki/Dutch_phonology#/media/File:Du...
[1] https://en.wikipedia.org/wiki/Dutch_phonology#/media/File:Du...