Questions about pronunciation and related issues seem to come up here quite frequently, and I've always felt that using the Korean alphabet to transcribe English is like shaving with a kitchen knife — I guess you could do it if you really wanted to, but it sure as hell is not the right tool for the job. I will talk about transcribing English pronunciation with hangeul and try to outline the many major issues it has. I'll be using IPA (the International Phonetic Alphabet) throughout, but I'll try to explain the symbols along the way.


Firstly, the obvious issue is the syllabic structure of Korean and the problems it brings to a language like English. Word and syllable stress are very important in English, and your pronunciation gets a lot less accurate if you start adding syllables to words that don't really have them. A one-syllable word like "wolves" can become three syllables long when written as 울브스, and that is a HUGE change. I know, however, that many of you are already aware of this problem, and will therefore not focus on it.


Let's discuss individual sounds instead, starting with consonants. The biggest issue here are sounds that Korean simply doesn't have, and there are quite a few of them: 


- [v] as in "very",

- [f], as in "few"

- [θ] as in "thing",

- [ð] as in "that",

- [z] as in "zebra",

- [ʃ] as in "shoe",

- [tʃ] as in "change",

- [ʒ] as in "vision",

- [dʒ] as in "gin".


Every time you write a word that contains any of the sounds above, you're only approximating its pronunciation. It wouldn't even be that big of an issue were the approximations actually accurate — and in many cases they are reasonably good, e.g. when writing ㅊ for "ch". However, many of them are very different from the English sounds, leading to a terribly inaccurate pronunciation of words. The biggest problem here, in my opinion, is that so many sounds are written the same way in Korean. [ʒ] in "vision" is ㅈ. [dʒ] in "gin" is ㅈ. [z] in "zebra" is ㅈ. In addition to making yourself harder to understand, you do not learn to differentiate these sounds by blindly following the Korean transcription.


Another flaw of 한글 as a transcription tool is the impossibility to distinguish between different "l" and "r" sounds, which I hope that many of you have already realised. The most common "r" sound in English, [ɹ] as in "red", does not exist in Korean at all. One of the "l" sounds, [l] as in "let", is fairly similar to the Korean equivalent, but the other very common "l" sound, dark l [ɫ] as in "ball", is also not present in Korean. Many English dialects also have r-coloured vowels (like [ɚ] at the end of "doctor" in American English), which Korean is simply not able to replicate. This causes a lot of confusion for Korean speakers relying on 한글 transcriptions and requires extra care.


A less important but still non-negligible issue is that the phonology of Korean is different than English. Writing "p" as ㅍ at the beginning of words is perfectly fine because it is the same sound in both languages — an aspirated [p], that is [pʰ] (aspirated means that you make a puff of air as you make the sound). However, this aspiration does not always occur, and "p" and ㅍ are definitely not equivalent. For example, the word "pin" is pronounced as [pʰɪn] (aspirated), but the word "spin" is just [spɪn], with no aspiration. The transcription 스핀 does not take that into consideration. In fact, 스삔 would be more accurate, because ㅃ is an unaspirated consonant. Generally, consonants in Korean behave in a different way than consonants in English, and when you transcribe a word in 한글 people will read it with Korean phonological rules — rules which do not apply to English.


Moving on to vowels, more and more problems pile up. Disregarding diphthongs (two vowels pronounced close together), standard Korean has about 7 or 8 vowels, depending on if and how you differentiate between 에 and 애. Out of these eight, 6 are close to vowels used in English. The problem is that English dialects can have anywhere between 11 and 15 vowels, likely even more. Once again, you have to rely on crude approximations to be able to write down English sounds using 한글.


I will list the single vowel sounds that, to my knowledge, standard Korean does not have:


- [ɪ] as in "big",

- [ʊ] as in "good" (note: this is NOT the same as [u:] in "food", which Korean does have),

- [æ] as in "cat",

- [ə] as in "again",

- r-coloured vowels [ɚ], [ɝ] mentioned above,

- [ɑ] as in standard American "dot" or southern British "bath",

- [ʌ] as in "nut".


(The sound [ɑ] is often lumped together with [a] in Korean and transcribed as 아. That is not a big problem whatsoever, the sounds are very similar.)


Vowels are terribly important in English, and learning to tell them apart is crucial to both understanding English and being understood in it. Again: you do not learn these sounds if you read Korean transcriptions, as they will use approximate sounds in place of the real ones. You lose a huge chunk of the English phonology that way, and you will struggle to understand people with different accents if you do not understand how vowels are used in English and how they change between dialects. You are doing yourself a huge disservice by relying on 한글 transcriptions.


I'm not even mentioning the problems with diphthongs here (such as transcribing "oh" as 오, being unable to transcribe something like "woo" reliably, and several others)!


As you can see, putting together the problems with consonants and vowels, the Korean alphabet comes off as an extremely unreliable method of transcribing English. It simply cannot constitute a good way to learn English pronunciation, and especially to understand the quirks and small differences between two similar pronunciations. 


Please stop relying on 한글 for English transcription. The alphabet was created for Korean and English is not a language that it can reliably represent.


EDIT:  See here for a Korean translation!