A large share of Korean vocabulary was borrowed from Chinese over several centuries, and those words are built from morphemes that recur constantly. Learn the morphemes and the words stop being individual items: the piece meaning study, the piece meaning place, the piece meaning person and the piece meaning study-hall combine and recombine across hundreds of nouns, in exactly the way components build characters elsewhere.
Which makes the useful unit the morpheme rather than the word, for about half of the language. The other half, the native Korean words, has to be learned one at a time, and that is where the everyday verbs and adjectives live.
Six items, and the two layers under the vocabulary
- 하나, 둘, 셋 and 일, 이, 삼, one two three, twice. Korean has two complete number systems, one native and one from Chinese.
- Sino-Korean and native numbers do different jobs. Native numbers count objects and hours; Sino-Korean numbers do minutes, money, dates and phone numbers. Telling the time uses both in one sentence.
- 학교 comes from Chinese, school, and roughly half the vocabulary is Sino-Korean, which means a learner of Chinese or Japanese arrives with a large head start.
- 오빠, 형, 언니, 누나, older brother and older sister, with different words depending on whether the speaker is male or female. Four words where English has two.
- 눈치, the ability to read a room and sense what is unsaid. It is a valued social skill with a single name and no English equivalent.
- Konglish, English derived words used in ways English does not: a mobile phone is a hand phone. Recognising these as Korean rather than as errors is part of learning the vocabulary.
Two vocabularies, one written script
The two layers behave differently in every way that matters. Native words are plainer, they carry the verbs and adjectives, and they inflect. Sino-Korean words are almost all nouns, they feel more formal, they are what a newspaper and a contract are made of, and they are assembled from a stock of shared pieces.
Frequently there is a word of each kind for the same idea and both are current, so choosing between them is a register decision rather than a vocabulary one. That is the same arrangement English has with its Germanic and Latin layers, and an English speaker's instinct about formality transfers once they know which layer they are looking at.
What Korean lacks is the thing that used to keep the Sino-Korean words apart. They were once written in Chinese characters and they are now written phonetically, so a great many of them are homophones distinguished only by context. That is a genuine cost, it falls entirely on listening, and it is the reason a Korean sentence often contains more disambiguating context than a translation would need.
Learning the Sino-Korean words as opaque items
Here is the stall, and it is the exact mistake a Chinese learner is taught to avoid. A learner meets a formal noun, cannot see inside it, and stores it whole. Then they meet the next one built from one of the same pieces and store that whole too. The vocabulary grows linearly when it could have been growing several times faster.
The exit is to spend a fortnight on the two or three hundred commonest Sino-Korean morphemes rather than on another two hundred words, which feels like a detour and is the highest return available in this subject. Anybody who has studied Chinese or Japanese characters already owns most of them and simply has to attach the Korean readings, which is a discount they can spend immediately. For everybody else it is new work with an unusually short payback, and the argument for front loading it is the same one made about roots elsewhere in this pillar.
From a word to a card
Which Korean words actually have to be stored
The second band is the one nobody applies, and it removes a large share of the formal vocabulary before it ever reaches a deck.
- Every word in the textIncluding several built from pieces you already own
- Not decodable from morphemesWhich removes much of the Sino-Korean layer once the pieces are learned
- Not a borrowing you can readThough it may still need a card for hearing it
- You will meet it againHonestly assessed, and usually overestimated
- Stored with what it needsThe register, and for a verb the stem it conjugates from
The bands carry no numbers because nobody has counted your reading. The claim is the order: applying the second filter before the fourth is what keeps a Korean deck to a size that can actually be reviewed.
Two references, one of them free
A list of the common Sino-Korean morphemes, studied for the meanings rather than for the characters, is the object to work through. It replaced learning each formal noun separately, which is what happens by default because dictionaries list words rather than parts. Free lists exist, and the characters themselves are optional here: a learner who does not want to study hanja can learn the pieces as syllables with meanings and get most of the benefit.
Wiktionary is the free lookup that shows the join. Its Korean entries give the origin of a word and, for Sino-Korean vocabulary, the characters behind each syllable, which is the fastest way to notice that two words you learned separately share a piece. It replaced the bilingual dictionary, which gives a gloss and hides the structure, and it is the tool that turns this page from advice into a habit.
The mistake: taking the English borrowings as free
There is a third and much smaller layer of words borrowed from English, and it looks like a gift for the same reasons it does elsewhere and is not one for the same reasons. The phonology reshapes the word, Korean syllables are built differently, and the result is frequently unrecognisable by ear even when it is obvious on the page.
The meanings also move. A borrowed word often covers a narrower sense than the original, and a fair number were assembled in Korean out of English parts and are not English words at all. So this layer has to be learned rather than assumed, and the specific thing to practise is hearing it, since reading it is the easy half. Which is the same lesson the numbers teach: the two counting systems both have to be learned because whichever one you skip is the one the next sentence needs.
What the words still need
A word learned from a page arrives without the sound changes that will reshape it in a sentence, and Korean applies those at every boundary, which is sounds that shift depending on their neighbours. The verbs among them take five layers of ending, in particles, and endings that change with who you address, and the last of those layers is a statement about the listener, in formal, polite and casual, and the cost of the wrong one. Reading any of it at speed depends on the blocks being automatic, in fourteen consonants, ten vowels, assembled into blocks. And whether a word earns a card at all is the general question in making cards that teach rather than cards that pile up.