Welcome to the Pronouncer blog, where we will be discussing the pronunciation of various languages and the related issue of how to transcribe them in various forms, especially into the Korean alphabet. Posts will be in English or Korean depending on the subject matter.
We will be dealing with subjects such as phonetics, phonology, orthography, transliteration, and transcription. To represent the pronunciations, we will be relying heavily on the International Phonetic Alphabet, so make sure to gain some familiarity with it.
In the above, [hə.ˈloʊ̯.ˈwɜrld] is a diaphonic phonetic transcription of the English utterance “Hello, world”, which is to say that it is a single phonetic transcription that covers pronunciation in both Received Pronunciation (RP) and General American (GA) pronunciation, the representative accents of British and American English respectively. For a phonetic transcription of RP, we would generally transcribe GB[hə.ˈləʊ̯.ˈwɜːld] instead, to show that the diphthong diaphonically transcribed as [oʊ̯] has a more unrounded, central starting point, hence GB[əʊ̯]; and that underlying [r] is not pronounced unless it is immediately followed by a vowel, which is why we write GB[ɜː] instead of [ɜr]. This is because RP is a non-rhotic accent, unlike GA. For the rhotic GA pronunciation, we follow many pronunciation dictionaries in preferring to show the r-coloured vowel explicitly for the combination [ɜr], writing US[ɝː] instead, i.e. US[hə.ˈloʊ̯.ˈwɝːld].
In general, we give phonetic transcriptions enclosed in square brackets ([ ]). Phonetic transcriptions are simply representations of the speech sounds, and can be broad or narrow based on how much detail we want to go into. A phonemic transcription, which we enclose in slashes (/ /), is a special kind of broad transcription where the symbols we use correspond one-to-one to the phonemes of the language, that is, the atomic unit of the sounds of a language. This requires determining the structure of the pronunciation of the language to determine precisely what the phonemes are, i.e. a phonological analysis. Different analyses may disagree on whether one sound is a phoneme in its own right or simply a variant of another phoneme, and the inventory of phonemes also varies depending on the different varieties of the language. In our case, /hə.ˈloʊ̯.ˈwɜrld/ could be a perfectly serviceable phonemic transcription, but we prefer to give phonetic transcriptions in general for English because we want to capture some details in pronunciation without worrying about whether they are relevant to phonemic differences.
What about [ˈhɛl.oʊ̯.ˈwɜrld]? Well, the first thing to know is that “hello” has an alternative pronunciation, [hɛ.ˈloʊ̯], which is the same as [hə.ˈloʊ̯] except that the first vowel is unreduced. Here I follow Wikipedia in transcribing the vowel of DRESS as [ɛ], but many simply write [e] (e.g. [he.ˈloʊ̯]) since it is just as unambiguous—English doesn’t have two e-type vowels to distinguish—and is the simpler symbol typographically.
Now, [ˈhɛl.oʊ̯] is a variant pronunciation where the stress is on the first syllable, though it is not recognized in many dictionaries. It does appear as an American variant in the Cambridge English Pronouncing Dictionary, 18th ed. But even if stressing “hello” on the first syllable is rare when the word is pronounced on its own, it is a different story when a stressed syllable immediately follows. “Hello” then becomes susceptible to stress shift so that it is pronounced [ˈhɛl.oʊ̯], and this even becomes the usual pronunciation in examples such as Hello Kitty [ˈhɛl.oʊ̯.ˈkɪt̬.i]. That is why I write [ˈhɛl.oʊ̯.ˈwɜrld] as a possibility.
I think I would oscillate between the two pronunciations, tending to say [hə.ˈloʊ̯.ˈwɝːld] if I was actually greeting the world, but tending more to [ˈhɛl.oʊ̯.ˈwɜrld] if it is a set phrase, as in a “Hello, world!” program.