Sino-Japanese

The expression Sino-Japanese refers to borrowings from the Chinese language as traditionally pronounced by speakers of Japanese. Chinese vocabulary has exerted an enormous effect on Japanese, partly because at the time of their first contact, Japanese had no written form. The earliest written language to be used in Japan was in fact literary Chinese, which has come to be called kanbun in this context. Use of kanbun essentially required every literate Japanese to be competent in written Chinese. However, it is unlikely that any more than a very small number of Japanese people were ever fluent in spoken Chinese. Instead, Chinese pronunciation was approximated; these approximations of Chinese pronunciation have become what is now called Sino-Japanese. Later, the modern system of kanji and kana was developed, which enabled Japanese itself to be written using Chinese-based characters. However, many Sino-Japanese words were taken into the general vocabulary as loanwords; these are the on'yomi readings of kanji.

Sino-Japanese is very important for comparative linguists as it provides a large amount of evidence to allow the reconstruction of Middle Chinese.

At first glance, many Sino-Japanese words will often not appear to be of Chinese origin at all. However, the observed differences are caused by the nature and history of the two languages involved, as well as the natural change of language over time. What follows is a rough guide for understanding equivalencies between modern Mandarin Chinese words and modern Sino-Japanese on'yomi readings. (Note: Unless otherwise noted, in the list below, sounds shown with in quotation marks, such "h" or "g", refer to Hanyu pinyin romanization for Chinese and Hepburn romanization for Japanese; shown within square brackets, such as [g] or [dʒ], refers to IPA transcription.)

1. A major sound-shift occurred in Mandarin since the time of modern contact with the West. Namely, the sounds written in Pinyin as [g] or [k], when immediately preceding an "i", "y" or "ü" sound, became "j" ([tɕ], similar to English "j") or "q" ([tɕʰ], similar to English "ch"). This change is called palatalization. As a result, Peking (北京) changed to Běijīng, and Chungking (重慶) to Chóngqìng). This shift is not reflected in Sino-Japanese. Thus, Chinese qì (氣, breath) corresponds to Japanese ki.
2. The Japanese language does not have an "-ng" sound, which it is very common in Chinese. This sound was borrowed as either [i] or [u]. The combinations [au] and [eu] later became "ō" and "yō" respectively in Japanese. Thus, the Mandarin Chinese reading of "Tokyo" is Dōngjīng; this corresponds to Japanese Tōkyō (東京), which means 'eastern capital' (keng -> keu -> kyō, note that kei is another reading of 'capital'). Note also that "Tokyo" is a Japanese invention, and not a direct borrowing from any Chinese language.
3. The vowels of Chinese will sometimes correspond apparently unpredictably to Sino-Japanese. However, we can note that Chinese "ao" often corresponds to Japanese "long o" and Chinese empty rime [ʅ] (represented in pinyin with a "i"), often corresponds to [i] (a different sound, also represented with a "i" in Hepburn) in Japanese.
4. The distinction between voiced and unvoiced consonants ([d] vs. [t] or [b] vs. [p]) has been lost in mondern Mandarin and many other Chinese languages. Thus a voiced consonsant in Japanese will correspond to an unvoiced one in Mandarin.
5. In modern Mandarin, syllables can only end in a vowel or in one of a small number of consonant sounds: "n", "ng", or occasionally "r". Premodern Chinese, as well as several modern Chinese languages like Cantonese, however, allow several other final consonants, such [k], [g], and [t], which are preserved in Sino-Japanese. However, because these consonants cannot appear at the end of words in Japanese either, they are usually followed in Sino-Japanese by an additional "i" or "u" vowel (as a result, a one-syllable word in Chinese can become two syllables in Japanese). For example, Chinese tiě (铁, iron) corresponds to Japanese tetsu (鉄). This is still pronounced with a final [t] in Cantonese: [tit].
6. The consonant "f" in Chinese corresponds to both "h" and "b" in Japanese. This is due to changes in Chinese; Japanese attempts to preserve the older forms, but itself has gone through phonological shifting. Thus, Chinese Fó (佛, Buddha) corresponds to Japanese Butsu (仏); both derive from the archaic Chinese [but]. Note that this pattern appears in Latin and English as well: Latin frater corresponds to English brother (even though the two words are derived from a common Indo-European root, the idea of a change in the pronunciation of consonants is the same; another example is the change of the initial f to h in certain verbs in Spanish when compared to Latin, thus 'hacer' from 'facio').
7. In addition, bilabial consonants have gone through numerous phonological shifts in both Chinese languages and Japanese since the time of borrowing. For example, 八 (eight) is "ba" in modern Mandarin Chinese, but "hachi" in modern Japanese. This shows that the "h" consonant in modern Japanese was closer to "p" in old Japanese. (Incidentally, this also explains why "h", "b", and "p" sounds share the same kana (hiragana はひふへほ, katakana ハヒフヘホ), and that these kana were derived from mostly "b" characters)
8. More complex is the archaic [v] sound: The character 武 (strife, martial arts) was pronounced "vu" in Middle Chinese, and is thus preserved in Hakka. The sound is approximated in the Japanese pronunciation "bu". However, [v] no longer exists in most modern Chinese languages, as the character is pronounced "wu" in Mandarin and "mu" in Cantonese.
9. The modern Chinese consonant "r" usually corresponds to "ny" or "ni" in Japanese. At the time of borrowing, characters that nowadays begin with "r" such as 人 and 日 began with a palatal nasal consonant[ɲ] closely approximating French and Italian "gn" and Spanish "ñ". (This distinction is still preserved in some Chinese languages such as Hakka today.) Thus Chinese Rìběn (日本, Japan) corresponds to Japanese Nippon. This is also why the character 人 is pronounced "nin" in some contexts, as in "ningen" (人間) and approximating the character's Middle Chinese pronunciation, and "jin" in others, such as "gaijin" (外人) (approximating its more modern pronunciation).
10. In Middle Chinese, 五 and similar characters were pronouned as a velar nasal consonant, "ng" ([ŋ]). This is no longer the case in modern Mandarin, but remains so in other Chinese languages such as Cantonese. Japanese approximates the Middle Chinese "ng" with "g" or "go", and thus 五 becomes "go".
11. The Chinese "hu" consonant sound (as in "huá" or "huī") does not exist in Japanese and is usually omitted, whereas the Chinese "l" sound becomes "r" in Japanese. Thus, Chinese Huángbò (黄檗) corresponds to Japanese Ōbaku, and Rúlái (如来) to Nyorai.
12. Chinese "h" will often correspond to "k" in Japanese. Old Japanese lacked an [h] sound; Modern Japanese [h] is derived from Old Japanese [p]. Chinese "z" will often correspond to "j"; these are also changes in Chinese. Thus, Chinese hànzì (漢字) corresponds to Japanese kanji, and hànwén (漢文, Chinese written language) to kanbun.