Comparison of Japanese and Korean

Korean and Japanese both have an agglutinative morphology in which verbs may function as prefixes[15] and a subject–object–verb (SOV) typology.[16][17][18] They are both topic-prominent, null-subject languages. Both languages extensively utilize turning nouns into verbs via the "to do" helper verbs (Japanese suru する; Korean hada 하다).

Modern Korean and Japanese share a similar system of proximal and distal demonstrative pronouns: i- (이), ku- (그) and jeo- (저) for Korean corresponding to the Japanese ko- (こ), so- (そ) and a- (あ) ("this", "that" and "that over there"). They both lack a compulsory distinction of plurality (for example "an apple" vs "apples" is usually not specifically distinguished).

Korean and Japanese also share the particle system. Korean and the Japonic languages are among the few extant languages in the world with topic markers. This allows words of different parts of speech to be placed in exactly the same order if some sentences are translated from one language to another. Such direct word for word swapping cannot be so easily done with any other languages, showing that Korean and Japanese are grammatically quite similar.

However, there are also many differences. One of the most significant grammatical differences between Japanese and Korean is the way of forming attributive verbs. Japanese doesn't have separate verb forms for attributive verbs, simply putting a predicative verb before a noun turns the verb into attributive. However, Korean uses distinct conjugations for making attributive verbs in three tenses. That means verb forms are more varied in Korean and word order is more flexible in Korean than it is in Japanese, since more verb forms give more grammatical hints. Old Japanese has distinct attributive verb forms as in Korean, but modern Japanese (except for the Hachijō language) has lost this feature, and displays a newly developed analytic tendency that is not observed in Korean.

Another notable difference is the use of the future tense. Japanese is considered to have two tenses; past and non-past, whereas Korean is considered to have three tenses; past, present and future. Korean uses distinct verb forms (-겠- , -ㄹ/-을, -리-) for the future tense, whereas Japanese uses the non-past (present) tense for future events, often with additional words (つもり、はず) and moods (〜だろう、〜でしょう). Note that not all linguists agree with the idea that Korean has three tenses. Some linguists argue that Korean has two tenses (past, present) or four tenses (greater past, past, present, future), and some even argue that Korean has no tense at all but only aspects. The three tenses theory is generally accepted but still remains controversial.

The Japanese perfective (〜て/〜でいる) has two meanings when the stem is an intransitive verb, and it depends on the context; the present perfect (e.g. 座っている; have sat down) or the present progressive (e.g. 走っている; be running). However, Korean uses two separate particles (-어/-아, -어서/-아서) and (-고) for (〜て/〜で) so they are morphologically different (e.g. 앉아 있다; have sat down, 앉고 있다; be sitting down). Some older dialects of Japanese had this distinction, and the Tosa dialect still makes clear distinction between the two meanings.

The Japanese predicative copula (〜だ、〜です) is used for both nouns (e.g. これは本だ; This is a book) and adjectives (e.g. これは有名だ; This is famous), with an exception to the い-adjectives which don't take the (〜だ) copula. In Korean, however, nouns and adjectives never share the same copula. The Korean copula (-이다/-다, -입니다, -이야/-야, -이에요/-예요) is only used for nouns (e.g. 이것은 책이다; This is a book) and some adverbs. Instead, the Korean 하다-adjectives — which are equivalent to the Japanese な-adjectives — share the same copula (-하다, -합니다, -해, -해요) with verbs (e.g. 이것은 유명하다; This is famous), with an exception to (-하다) which takes a different form (-한다) for verbs. In contrast, verbs and adjectives never share the same copula in Japanese. The equivalent Japanese copula (〜する、〜します) is usually used for verbs (with exceptions like つるつるする). It's controversial among grammarians whether to consider "な-adjectives" like 有名 as adjectives at all, with many considering them nouns or quasi-adjectives.

Japanese uses two words (いる) and (ある) for (있다) in Korean. In the past, Japanese also only used one word. This is preserved in the Hachijō language. Korean uses two words (없다) and (않다) for (ない) in Japanese. Japanese often uses similar words (なに/なん/なんの) to include what would be either 'what' or 'how many' in English without specific distinction (the context of being next to a counter word makes the meaning clear), while Korean has an extra word specifically used with counter words to express "how many" (무엇/뭐/무슨; 몇).

The two languages are also quite different in regards to the grammatical cases. The Japanese genitive marker no (の) is regularly used between nouns but the Korean genitive marker ui (의) is often omitted otherwise it's considered unnatural. Another notable difference is the vocative case commonly used in Korean. Japanese also has similar particles (〜よ、〜や) working like the vocative case in Korean but the usage is very limited.

In both languages, passive and causative verbs have important roles. The rules for forming passive and causative verbs are more regular and logical in Japanese. In Korean, passive and causative verbs do have some predictable patterns, but without enough consistency to make some rules about it. It is comparable to the past participles in English. The past participles in English do have some predictable patterns such as '-ed' (e.g. walked, worked), '-en' (e.g. eaten, gotten), but the consistency is not enough to make a rule about it. Korean has about nine possible patterns for passive verbs and ten possible patterns for causative verbs, but without a certain consistency.

The two languages have previously been thought to not share any cognates (other than loanwords),[4] for their vocabularies do not phonetically resemble each other. However, a 2016 paper proposing a common lineage between Korean and Japanese traces around 500 core words thought to share a common origin.[19] Most resembling lexicon in the study has been observed between Middle Korean (15th century) and earlier Old Japanese (8th century), some of which is shown in the following table:

Although fewer in number, there have been also comparisons between stages other than Old Japanese and Middle Korean:

In addition to the above, there may be a relation between the words for morning (朝, asa; 아침, achim). A historical variant in Korean may have been pronounced "asa" (see: Asadal). There is also a minority theory attributing the name of the city Nara to a loanword from Korean (see: Nara, Nara#Etymology).

Phonetically, Korean and Japanese have a similarly limited inventory of vowel sounds, and both Japanese and old Korean (and some dialects of Korean) make use of vowel length.

Korean particles and polite grammatical ending conjugations can sometimes share a superficial similarity with Japanese. The Japanese particle が (ga) is similar to the particle 가 (ka) in function and sound. The informal and impolite conjugation of Korean's Copula 야 (ya) is similar to the dialectal informal copula や (ya) in Japanese (corresponding to だ in standardized Japanese).

Functionally, some peculiar aspects of particles and particle usage are also the same in both languages. For example, the particles 도 (*do*) and も (*mo*) not only share an inclusive function (similar to "too" in English), they also both function to emphasize sheer lack in negative sentences, or sheer intensity in positive sentences. 에 (e) and へ (he) have similar sounds, and one of 에's usages is similar to へ. Particles are also used in the same way to form basic vocabulary words. I.e., 도 (do) and も (mo) in the words for *no one* (아무도, 誰も), and the similar sounding 가 (ga) and か (ka) particle sometimes adding an unknown/questioning element to a word to form the equivalent meaning to English *some*, (i.e. in 뭔가 and 何か, meaning *something*).

However, some percentage of vocabulary in any language may be expected to resemble vocabulary in any other language to a certain extent through random coincidence. The likelihood that a word in one language will be perceived as resembling a word in another language is inversely correlated with the number of phonemes in the word (i.e. the shorter a word is, the more likely it will randomly resemble a short word in another language) and positively correlated with the degree of overlap in the languages' phonological systems (i.e. the more similar the sound systems of the two languages, the more likely it is that any word from one language will be perceived as sounding similar to a word from the other language).

Both languages use, to some extent, a combination of native scripts and Chinese characters.

Korean is mostly written in the Korean featural alphabet (known as Hangul in South Korea and Chosŏn'gŭl in North Korea). The traditional hanja (Chinese characters adapted for Korean) are sometimes used in South Korea, but only for specific purposes such as to clarify homophones (especially in TV show subtitles), linguistic or historic study, artistic expression, legal documents, and newspapers. Native Korean words do not use hanja anymore. In North Korea, the hanja have been largely suppressed in an attempt to remove Sinic influence, although they are still used in some cases and the number of hanja taught in North Korean schools is greater than that of South Korean schools.[22]

Japanese is written with a combination of kanji (Chinese characters adapted for Japanese) and kana (two writing systems representing the same sounds, composed primarily of syllables, each used for different purposes).[23][24] Unlike Korean hanja, however, kanji can be used to write both Sino-Japanese words and native Japanese words.

Historically, both Korean and Japanese were written solely with Chinese characters, with the writing experiencing a gradual mutation through centuries into its modern form.[25]

Both languages have similar elaborate, multilevel systems of honorifics, and furthermore both Korean and Japanese also separate the concept of honorifics from formality in speech and writing in their own ways (See Korean speech levels and Honorific speech in Japanese § Grammatical overview). They are cited as the two most elaborate honorific systems, perhaps unrivaled by any other languages.[26] It has been argued that certain honorific words may share a common origin.[27] Uniquely, the honorifics rely heavily on changing verb conjugations rather than only using t-v distinction or other common methods of signifying honorifics. See Korean honorifics and Japanese honorifics.

• Baekje language
• Classification of the Japonic languages
  • Classification of Japonic languages#Similarities between Japanese and Koreanic languages
• Japonic languages
• Koreanic languages
• Peninsular Japonic