Fortunately, there is a nice long list of reasons to be happy about the Korean sound system:
- No voiced/unvoiced distinctions: Korean does not use voicing of consonants as a meaningful feature, so there are no minimal pairs distinguished by voicing. This is in sharp contrast to English where voicing is the feature distinguishing word pairs like fat/vat, big/pig, sit/zit, tank/dank, sang/sank and many other.
- Smaller consonant inventory and no unfamiliar consonants: Mostly because of the lack of voicing distinction, the Korean consonant inventory is smaller than that of English. There are also no new, unfamiliar consonants that would take practice to learn, such as pharyngeal fricatives or epiglottal plosives or trills or implosives or clicks. (However, see the final item in the Bad section below about aspirated and tense consonants.)
- No difficult consonant clusters: Korean phonotactics are pleasantly restrictive, such that the language has very few consonant clusters (sequences of consonants with no intervening vowels) and most of them involve easily-flowing nasals. Considering that English has common mouthfuls like sixths /sɪksθs/ and sphinx /sfɪŋks/, simple phonotactics are very welcome.
- Familiar vowels: Almost all Korean vowels and diphthongs map directly to existing English sounds. I’m sure correct pronunciation will take practice, but that is to be expected.
- No tones: Korean apparently once had four tones, similar to Mandarin Chinese, that were included in the original Hangul system. These ceased to be a meaningful part of the Korean sound system around the 1600s.
- No meaningful vowel length: Until more recently the language also had meaningful vowel length, where two otherwise identical words were distinguished by the length of the vowels spoken. But meaningful vowel length appears to be almost extinct in Modern Korean.
- Grapheme-to-phoneme mappings are (mostly) unambiguous: As I’ve already written, the Korean writing system was designed so that characters map directly to phonemes in the spoken language. Despite being 650 years old, this mapping is still quite clear. In addition, the writing system includes a transparent means for representing syllables. This will greatly assist in grammar and vocabulary acquisition.
- Phonological transformation: As with any language, Korean has some context-dependent phonological transformations (substitutions of certain sounds for others based on word position or surrounding sounds). But these are mostly regular and easy to learn.
There is a mercifully short list of just two elements that will require some extra effort to learn to produce and recognize reliably:
- Unreleased final consonants: Most word-final consonants are unreleased, which sometimes changes the sound to an unreleased [ t̚ ] (e.g., /kis/ becomes [kit̚ ]) and sometimes makes the consonant sound nearly inaudible (e.g., /hanguk/ becomes [hanguk̚ ] but actually sounds more like [hangu]). In learning to pronounce new written words, this is not so much a problem since the transformation rules are regular and predictable. However, it will likely create challenges for listening comprehension, until the words become more familiar.
- Aspiration and tenseness as meaningful consonant features: Korean makes up for the lack of voicing distinctions in consonants by including separate sets of phonemes for three degrees of aspiration and tenseness. Each of these is conveniently represented by a separate Hangul character. For example, there is ㅂ(a lax /p/), ㅍ (a heavily aspirated /pʰ/) and ㅃ (a tense or double /pp/). Since these differences are not meaningful in English, my initial attempts to distinguish them (and generate them, for that matter) have been largely unsuccessful.
There really appears to be no truly difficult part of the Korean sound system, which, combined with the intuitive writing system, will make early progress rapid. But since the phonology doesn’t seem scary, I expect some elements of the grammar and vocabulary are going to be extra difficult to learn.