Japanese (日本語,Nihongo,[ɲihoŋɡo]or[ɲihoŋŋo] ( ) ) is an East Asian language spoken by about 126 million people, primarily in Japan, where it is the national language. It is a member of the Japonic (or Japanese- Ryukyuan) language family, and its relation to other languages, such as Korean, is debated. Japanese has been grouped with language families such as Ainu, Austroasiatic, and the now-discredited Altaic. None of these proposals has gained widespread acceptance, however.
Little is known of the language's prehistory, or when it first appeared in Japan. Chinese documents from the 3rd century recorded a few Japanese words, but substantial texts did not appear until the 8th century. During the Heian period (794–1185), Chinese had considerable influence on the vocabulary and phonology of Old Japanese. Late Middle Japanese (1185–1600) included changes in features that brought it closer to the modern language, and the first appearance of European loanwords. The standard dialect moved from the Kansai region to the Edo (modern Tokyo) region in the Early Modern Japanese period (early 17th century–mid-19th century). Following the end in 1853 of Japan's self-imposed isolation, the flow of loanwords from European languages increased significantly. English loanwords, in particular, have become frequent, and Japanese words from English roots have proliferated.
Japanese is an agglutinative, mora -timed language with simple phonotactics, a pure vowel system, phonemic vowel and consonant length, and a lexically significant pitch-accent. Word order is normally subject–object–verb with particles marking the grammatical function of words, and sentence structure is topic–comment. Sentence-final particles are used to add emotional or emphatic impact, or make questions. Nouns have no grammatical number or gender, and there are no articles. Verbs are conjugated, primarily for tense and voice, but not person. Japanese equivalents of adjectives are also conjugated. Japanese has a complex system of honorifics with verb forms and vocabulary to indicate the relative status of the speaker, the listener, and persons mentioned.
Japanese has no genetic relationship with Chinese,  but it makes extensive use of Chinese characters, or kanji (漢字), in its writing system, and a large portion of its vocabulary is borrowed from Chinese. Along with kanji, the Japanese writing system primarily uses two syllabic (or moraic) scripts, hiragana (ひらがな or 平仮名) and katakana (カタカナ or 片仮名). Latin script is used in a limited fashion, such as for imported acronyms, and the numeral system uses mostly Arabic numerals alongside traditional Chinese numerals.
A common ancestor of Japanese and Ryukyuan languages or dialects is thought to have been brought to Japan by settlers coming from either continental Asia or nearby Pacific islands sometime in the early- to mid-2nd century BC (the Yayoi period), replacing the languages of the original Jōmon inhabitants, including the ancestor of the modern Ainu language. Very little is known about the Japanese of this period. Because writing like the "Kanji" which later devolved into the writing systems "Hirigana" and "Katakana"  had yet to be introduced from China, there is no direct evidence, and anything that can be discerned about this period of Japanese must be based on the reconstructions of Old Japanese.
Old Japanese is the oldest attested stage of the Japanese language. Through the spread of Buddhism, the Chinese writing system was imported to Japan. The earliest texts found in Japan are written in Classical Chinese, but they may have been meant to be read as Japanese by the kanbun method. Some of these Chinese texts show the influences of Japanese grammar, such as the word order (for example, placing the verb after the object). In these hybrid texts, Chinese characters are also occasionally used phonetically to represent Japanese particles. The earliest text, the Kojiki, dates to the early 8th century, and was written entirely in Chinese characters. The end of Old Japanese coincides with the end of the Nara period in 794. Old Japanese uses the Man'yōgana system of writing, which uses kanji for their phonetic as well as semantic values. Based on the Man'yōgana system, Old Japanese can be reconstructed as having 88 distinct syllables. Texts written with Man'yōgana use two different kanji for each of the syllables now pronounced き ki, ひ hi, み mi, け ke, へ he, め me, こ ko, そ so, と to, の no, も mo, よ yo and ろ ro. (The Kojiki has 88, but all later texts have 87. The distinction between mo 1 and mo 2 apparently was lost immediately following its composition.) This set of syllables shrank to 67 in Early Middle Japanese, though some were added through Chinese influence.
Due to these extra syllables, it has been hypothesized that Old Japanese's vowel system was larger than that of Modern Japanese – it perhaps contained up to eight vowels. According to Shinkichi Hashimoto, the extra syllables in Man'yōgana derive from differences between the vowels of the syllables in question. These differences would indicate that Old Japanese had an eight-vowel system, in contrast to the five vowels of later Japanese. The vowel system would have to have shrunk some time between these texts and the invention of the kana (hiragana and katakana) in the early 9th century. According to this view, the eight-vowel system of ancient Japanese would resemble that of the Uralic and Altaic language families. However, it is not fully certain that the alternation between syllables necessarily reflects a difference in the vowels rather than the consonants – at the moment, the only undisputed fact is that they are different syllables. A newer reconstruction of ancient Japanese show strikingly similarities with Southeast-Asian languages, especially with Austronesian languages. 
Old Japanese does not have /h/, but rather /ɸ/ (preserved in modern fu, /ɸɯ/ ), which has been reconstructed to an earlier * /p/. Man'yōgana also has a symbol for /je/, which merges with /e/ before the end of the period.
Several fossilizations of Old Japanese grammatical elements remain in the modern language – the genitive particle tsu (superseded by modern no) is preserved in words such as matsuge ("eyelash", lit. "hair of the eye"); modern mieru ("to be visible") and kikoeru ("to be audible") retain what may have been a mediopassive suffix - yu(ru) (kikoyu → kikoyuru (the attributive form, which slowly replaced the plain form starting in the late Heian period) > kikoeru (as all shimo-nidan verbs in modern Japanese did)); and the genitive particle ga remains in intentionally archaic speech.
Early Middle Japanese
Early Middle Japanese is the Japanese of the Heian period, from 794 to 1185. Early Middle Japanese sees a significant amount of Chinese influence on the language's phonology – length distinctions become phonemic for both consonants and vowels, and series of both labialised (e.g. kwa) and palatalised (kya) consonants are added. Intervocalic /ɸ/ merges with /w/ by the 11th century. The end of Early Middle Japanese sees the beginning of a shift where the attributive form (Japanese rentaikei) slowly replaces the uninflected form (shūshikei) for those verb classes where the two were distinct.
Late Middle Japanese
Late Middle Japanese covers the years from 1185 to 1600, and is normally divided into two sections, roughly equivalent to the Kamakura period and the Muromachi period, respectively. The later forms of Late Middle Japanese are the first to be described by non-native sources, in this case the Jesuit and Franciscan missionaries; and thus there is better documentation of Late Middle Japanese phonology than for previous forms (for instance, the Arte da Lingoa de Iapam ). Among other sound changes, the sequence /au/ merges to /ɔː/, in contrast with /oː/; /p/ is reintroduced from Chinese; and /we/ merges with /je/. Some forms rather more familiar to Modern Japanese speakers begin to appear – the continuative ending - te begins to reduce onto the verb (e.g. yonde for earlier yomite ), the -k- in the final syllable of adjectives drops out (shiroi for earlier shiroki ); and some forms exist where modern standard Japanese has retained the earlier form (e.g. hayaku > hayau > hayɔɔ, where modern Japanese just has hayaku, though the alternative form is preserved in the standard greeting o-hayō gozaimasu "good morning"; this ending is also seen in o-medetō "congratulations", from medetaku ).
Late Middle Japanese has the first loanwords from European languages – now-common words borrowed into Japanese in this period include pan ("bread") and tabako ("tobacco", now "cigarette"), both from Portuguese.
Early Modern Japanese
Early Modern Japanese, not to be confused with Modern Japanese, was the dialect used after the Meiji Restoration. Because the two languages are extremely similar, Early Modern Japanese is commonly referred to as Modern Japanese. Early Modern Japanese gradually evolved into Modern Japanese during the 19th century. Only after 1945, shortly after World War II, did Modern Japanese become the standard language, seeing use in most official communications. In this time period the Japanese in addition to their use of Katakana and Hirigana they also used traditional Chinese characters called " Han " which later developed in "Kanji" which is a form of writing used to express ideas in the Japanese and Chinese languages.
Modern Japanese is considered to begin with the Edo period, which lasted between 1603 and 1868. Since Old Japanese, the de facto standard Japanese had been the Kansai dialect, especially that of Kyoto. However, during the Edo period, Edo (now Tokyo) developed into the largest city in Japan, and the Edo-area dialect became standard Japanese. Since the end of Japan's self-imposed isolation in 1853, the flow of loanwords from European languages has increased significantly. The period since 1945 has seen a large number of words borrowed from languages, like German, Portuguese and English. Many English loan words especially relate to technology—for example, pasokon (short for "personal computer"); intānetto ("internet"), and kamera ("camera"). Due to the large quantity of English loanwords, modern Japanese has developed a distinction between /tɕi/ and /ti/, and /dʑi/ and /di/, with the latter in each pair only found in loanwords.
Although Japanese is spoken almost exclusively in Japan, it has been spoken outside. Before and during World War II, through Japanese annexation of Taiwan and Korea, as well as partial occupation of China, the Philippines, and various Pacific islands,  locals in those countries learned Japanese as the language of the empire. As a result, many elderly people in these countries can still speak Japanese.
Japanese emigrant communities (the largest of which are to be found in Brazil,  with 1.4 million to 1.5 million Japanese immigrants and descendants, according to Brazilian IBGE data, more than the 1.2 million of the United States ) sometimes employ Japanese as their primary language. Approximately 12% of Hawaii residents speak Japanese,  with an estimated 12.6% of the population of Japanese ancestry in 2008. Japanese emigrants can also be found in Peru, Argentina, Australia (especially in the eastern states), Canada (especially in Vancouver where 1.4% of the population has Japanese ancestry  ), the United States (notably California, where 1.2% of the population has Japanese ancestry, and Hawaii), and the Philippines (particularly in Davao and Laguna).   
Japanese has no official status,  but is the de facto national language of Japan. There is a form of the language considered standard: hyōjungo (標準語), meaning "standard Japanese", or kyōtsūgo (共通語), "common language". The meaning of the two terms are almost the same. Hyōjungo or kyōtsūgo is a conception that forms the counterpart of dialect. This normative language was born after the Meiji Restoration (明治維新,meiji ishin, 1868) from the language spoken in the higher-class areas of Tokyo (see Yamanote). Hyōjungo is taught in schools and used on television and even in official communications. It is the version of Japanese discussed in this article.
Formerly, standard Japanese in writing (文語,bungo, "literary language") was different from colloquial language (口語,kōgo). The two systems have different rules of grammar and some variance in vocabulary. Bungo was the main method of writing Japanese until about 1900; since then kōgo gradually extended its influence and the two methods were both used in writing until the 1940s. Bungo still has some relevance for historians, literary scholars, and lawyers (many Japanese laws that survived World War II are still written in bungo, although there are ongoing efforts to modernize their language). Kōgo is the dominant method of both speaking and writing Japanese today, although bungo grammar and vocabulary are occasionally used in modern Japanese for effect.
Dozens of dialects are spoken in Japan. The profusion is due to many factors, including the length of time the Japanese Archipelago has been inhabited, its mountainous island terrain, and Japan's long history of both external and internal isolation. Dialects typically differ in terms of pitch accent, inflectional morphology, vocabulary, and particle usage. Some even differ in vowel and consonant inventories, although this is uncommon.
The main distinction in Japanese accents is between Tokyo-type (東京式,Tōkyō-shiki) and Kyoto-Osaka-type (京阪式,Keihan-shiki). Within each type are several subdivisions. Kyoto-Osaka-type dialects are in the central region, roughly formed by Kansai, Shikoku, and western Hokuriku regions.
Dialects from peripheral regions, such as Tōhoku or Kagoshima, may be unintelligible to speakers from the other parts of the country. There are some language islands in mountain villages or isolated islands such as Hachijō-jima island whose dialects are descended from the Eastern dialect of Old Japanese. Dialects of the Kansai region are spoken or known by many Japanese, and Osaka dialect in particular is associated with comedy (see Kansai dialect). Dialects of Tōhoku and North Kantō are associated with typical farmers.
The Ryūkyūan languages, spoken in Okinawa and the Amami Islands (politically part of Kagoshima), are distinct enough to be considered a separate branch of the Japonic family; not only is each language unintelligible to Japanese speakers, but most are unintelligible to those who speak other Ryūkyūan languages. However, in contrast to linguists, many ordinary Japanese people tend to consider the Ryūkyūan languages as dialects of Japanese. This is the result of the official language policy of the Japanese government, which has declared these languages to be dialects and prohibited their use in schools.
The imperial court also seems to have spoken an unusual variant of the Japanese of the time.  Most likely being the spoken form of Classical Japanese language, a writing style that was prevalent during the Heian period, but began decline during the late Meiji period.
Japanese is a member of the Japonic languages family, which also includes the languages spoken throughout the Ryūkyū Islands. As these closely related languages are commonly treated as dialects of the same language, Japanese is often called a language isolate.
According to Martine Irma Robbeets, Japanese has been subject to more attempts to show its relation to other languages than any other language in the world. Since Japanese first gained the consideration of linguists in the late 19th century, attempts have been made to show its genealogical relation to languages or language families such as Ainu, Korean, Chinese, Tibeto-Burman, Ural-Altaic, Altaic, Uralic, Mon–Khmer, Malayo-Polynesian and Ryukyuan. At the fringe, some linguists have suggested a link to Indo-European languages, including Greek, and to Lepcha. As it stands, only the link to Ryukyuan has wide support, though linguist Kurakichi Shiratori maintained that Japanese was a language isolate.
Similarities between Korean and Japanese were noted by Arai Hakuseki in 1717, and the idea that the two might be related was first proposed in 1781 by Japanese scholar Teikan Fujii. The idea received little attention until William George Aston proposed it again in 1879. Japanese scholar Shōsaburō Kanazawa took it up in 1910, as did Shinpei Ogura in 1934. Shirō Hattori was nearly alone when he criticised these theories in 1959. Samuel Martin furthered the idea in 1966 with his "Lexical evidence relating Korean to Japanese", as did John Whitman with his dissertation on the subject in 1985. Despite this, definitive proof of the relation has yet to be provided. Historical linguists studying Japanese and Korean tend to accept the genealogical relation, while general linguists and historical linguists in Japan and Korea have remained skeptical.
Alexander Vovin suggests that, while typologically modern Korean and Japanese share similarities that sometimes allow word-to-word translations, studies of the pre-modern languages show greater differences. According to Vovin, this suggests linguistic convergence rather than divergence, which he believes is amongst the evidence of the languages not having a genealogical connection.
The largely discredited Altaic family, which would include languages from far eastern Europe to northeastern Asia, has had its supporters and detractors over its history. The most controversial aspect of the hypothesis is the proposed inclusion of Korean and Japanese, which even some proponents of Altaic have rejected. Philipp Franz von Siebold suggested the connection in 1832, but the inclusion first attracted significant attention in the early 1970s. Roy Andrew Miller published Japanese and the Other Altaic Languages, and dedicated much of his later career to the subject. Sergei Starostin published a 1991 monograph which was another significant stepping stone in Japanese—Altaic research. A team of scholars made a database of Altaic etymologies available over the internet, from which the three-volume Etymological Dictionary of the Altaic Languages was published in 2003. Scholars such as Yevgeny Polivanov and Yoshizo Itabashi, on the other hand, have proposed a hybrid origin of Japanese, in which Austronesian and Altaic elements became mixed. 
Skepticism over the Japanese relation to Altaic is widespread among Altaic's proponents, in part because of a large number of unsuccessful attempts to establish genealogical relationships with Japanese and other languages. Opinions are polarized, with many strongly convinced of the Altaic relation, and others strongly convinced of the lack of one. While some sources are undecided, often strong proponents of either view will not even acknowledge the claims of the other side.
Southeast Asian languages
Japanese shows in its proto-form strong similarities to Southeast Asian languages. A 2015 analysis using the Automated Similarity Judgment Program resulted in the Japonic languages being grouped with the Ainu and then with the Austroasiatic languages.
Some Japanese consonants have several allophones, which may give the impression of a larger inventory of sounds. However, some of these allophones have since become phonemic. For example, in the Japanese language up to and including the first half of the 20th century, the phonemic sequence /ti/ was palatalized and realized phonetically as [tɕi], approximately chi ; however, now /ti/ and /tɕi/ are distinct, as evidenced by words like tī [tiː] "Western style tea" and chii [tɕii] "social status".
The "r" of the Japanese language (technically a lateral apical postalveolar flap), is of particular interest, sounding to most English speakers to be something between an "l" and a retroflex "r" depending on its position in a word. The "g" is also notable; unless it starts a sentence, it is pronounced /ŋ/, like the ng in "sing," in the Kanto prestige dialect and in other eastern dialects.
The syllabic structure and the phonotactics are very simple: the only consonant clusters allowed within a syllable consist of one of a subset of the consonants plus /j/. This type of cluster only occurs in onsets. However, consonant clusters across syllables are allowed as long as the two consonants are a nasal followed by a homorganic consonant. Consonant length (gemination) is also phonemic.
The phonology of Japanese also includes a pitch accent system, which is a system that helps differentiate words with identical Hiragana spelling or words in different Japanese dialects. An example of words with identical Hiragana would be the words [haꜜ.shi] (chopsticks) and [ha.shiꜜ] (bridge), both spelled (はし, hashi) in Hiragana. The stresses differentiate the words. 
Japanese word order is classified as subject–object–verb. Unlike many Indo-European languages, the only strict rule of word order is that the verb must be placed at the end of a sentence (possibly followed by sentence-end particles). This is because Japanese sentence elements are marked with particles that identify their grammatical functions.
The basic sentence structure is topic–comment. For example, Kochira wa Tanaka-san desu (こちらは田中さんです ). kochira ("this") is the topic of the sentence, indicated by the particle wa. The verb de aru (desu is a contraction of its polite form de arimasu) is a copula, commonly translated as "to be" or "it is" (though there are other verbs that can be translated as "to be"), though technically it holds no meaning and is used to give a sentence 'politeness'. As a phrase, Tanaka-san desu is the comment. This sentence literally translates to "As for this person, (it) is Mr./Ms. Tanaka." Thus Japanese, like many other Asian languages, is often called a topic-prominent language, which means it has a strong tendency to indicate the topic separately from the subject, and that the two do not always coincide. The sentence Zō wa hana ga nagai (象は鼻が長い) literally means, "As for elephant(s), (the) nose(s) (is/are) long". The topic is zō "elephant", and the subject is hana "nose".
In Japanese, the subject or object of a sentence need not be stated if it is obvious from context. As a result of this grammatical permissiveness, there is a tendency to gravitate towards brevity; Japanese speakers tend to omit pronouns on the theory they are inferred from the previous sentence, and are therefore understood. In the context of the above example, hana-ga nagai would mean "[their] noses are long," while nagai by itself would mean "[they] are long." A single verb can be a complete sentence: Yatta! (やった! )"[I / we / they / etc] did [it]!". In addition, since adjectives can form the predicate in a Japanese sentence (below), a single adjective can be a complete sentence: Urayamashii! (羨ましい! )"[I'm] jealous [of it]!".
While the language has some words that are typically translated as pronouns, these are not used as frequently as pronouns in some Indo-European languages, and function differently. In some cases Japanese relies on special verb forms and auxiliary verbs to indicate the direction of benefit of an action: "down" to indicate the out-group gives a benefit to the in-group; and "up" to indicate the in-group gives a benefit to the out-group. Here, the in-group includes the speaker and the out-group does not, and their boundary depends on context. For example, oshiete moratta (教えてもらった) (literally, "explained" with a benefit from the out-group to the in-group) means "[he/she/they] explained [it] to [me/us]". Similarly, oshiete ageta (教えてあげた) (literally, "explained" with a benefit from the in-group to the out-group) means "[I/we] explained [it] to [him/her/them]". Such beneficiary auxiliary verbs thus serve a function comparable to that of pronouns and prepositions in Indo-European languages to indicate the actor and the recipient of an action.
Japanese "pronouns" also function differently from most modern Indo-European pronouns (and more like nouns) in that they can take modifiers as any other noun may. For instance, one does not say in English:
- *The amazed he ran down the street. (grammatically incorrect insertion of a pronoun)
But one can grammatically say essentially the same thing in Japanese:
- Odoroita kare wa michi o hashitte itta. (grammatically correct)
This is partly because these words evolved from regular nouns, such as kimi "you" (君 "lord"), anata "you" (あなた "that side, yonder"), and boku "I" (僕 "servant"). This is why some linguists do not classify Japanese "pronouns" as pronouns, but rather as referential nouns, much like Spanish usted (contracted from vuestra merced, "your [(flattering majestic) plural ] grace") or Portuguese o senhor. Japanese personal pronouns are generally used only in situations requiring special emphasis as to who is doing what to whom.
The choice of words used as pronouns is correlated with the sex of the speaker and the social situation in which they are spoken: men and women alike in a formal situation generally refer to themselves as watashi (私 "private") or watakushi (also 私 ), while men in rougher or intimate conversation are much more likely to use the word ore (俺 "oneself", "myself") or boku. Similarly, different words such as anata, kimi, and omae (お前, more formally 御前 "the one before me") may be used to refer to a listener depending on the listener's relative social position and the degree of familiarity between the speaker and the listener. When used in different social relationships, the same word may have positive (intimate or respectful) or negative (distant or disrespectful) connotations.
Japanese often use titles of the person referred to where pronouns would be used in English. For example, when speaking to one's teacher, it is appropriate to use sensei (先生, teacher), but inappropriate to use anata. This is because anata is used to refer to people of equal or lower status, and one's teacher has higher status.
Inflection and conjugation
Japanese nouns have no grammatical number, gender or article aspect. The noun hon (本) may refer to a single book or several books; hito (人) can mean "person" or "people", and ki (木) can be "tree" or "trees". Where number is important, it can be indicated by providing a quantity (often with a counter word) or (rarely) by adding a suffix, or sometimes by duplication (e.g. 人人, hitobito, usually written with an iteration mark as 人々 ). Words for people are usually understood as singular. Thus Tanaka-san usually means Mr./Ms. Tanaka. Words that refer to people and animals can be made to indicate a group of individuals through the addition of a collective suffix (a noun suffix that indicates a group), such as -tachi, but this is not a true plural: the meaning is closer to the English phrase "and company". A group described as Tanaka-san-tachi may include people not named Tanaka. Some Japanese nouns are effectively plural, such as hitobito "people" and wareware "we/us", while the word tomodachi "friend" is considered singular, although plural in form.
Verbs are conjugated to show tenses, of which there are two: past and present (or non-past) which is used for the present and the future. For verbs that represent an ongoing process, the -te iru form indicates a continuous (or progressive) aspect, similar to the suffix ing in English. For others that represent a change of state, the -te iru form indicates a perfect aspect. For example, kite iru means "He has come (and is still here)", but tabete iru means "He is eating".
Questions (both with an interrogative pronoun and yes/no questions) have the same structure as affirmative sentences, but with intonation rising at the end. In the formal register, the question particle -ka is added. For example, ii desu (いいです) "It is OK" becomes ii desu-ka (いいですか。) "Is it OK?". In a more informal tone sometimes the particle -no (の) is added instead to show a personal interest of the speaker: Dōshite konai-no? "Why aren't (you) coming?". Some simple queries are formed simply by mentioning the topic with an interrogative intonation to call for the hearer's attention: Kore wa? "(What about) this?"; O-namae wa? (お名前は？) "(What's your) name?".
Negatives are formed by inflecting the verb. For example, Pan o taberu (パンを食べる。) "I will eat bread" or "I eat bread" becomes Pan o tabenai (パンを食べない。) "I will not eat bread" or "I do not eat bread". Plain negative forms are actually i -adjectives (see below) and inflect as such, e.g. Pan o tabenakatta (パンを食べなかった。) "I did not eat bread".
The so-called -te verb form is used for a variety of purposes: either progressive or perfect aspect (see above); combining verbs in a temporal sequence (Asagohan o tabete sugu dekakeru "I'll eat breakfast and leave at once"), simple commands, conditional statements and permissions (Dekakete-mo ii? "May I go out?"), etc.
The word da (plain), desu (polite) is the copula verb. It corresponds approximately to the English be, but often takes on other roles, including a marker for tense, when the verb is conjugated into its past form datta (plain), deshita (polite). This comes into use because only i -adjectives and verbs can carry tense in Japanese. Two additional common verbs are used to indicate existence ("there is") or, in some contexts, property: aru (negative nai) and iru (negative inai ), for inanimate and animate things, respectively. For example, Neko ga iru "There's a cat", Ii kangae-ga nai "[I] haven't got a good idea".
The verb "to do" (suru, polite form shimasu) is often used to make verbs from nouns (ryōri suru "to cook", benkyō suru "to study", etc.) and has been productive in creating modern slang words. Japanese also has a huge number of compound verbs to express concepts that are described in English using a verb and an adverbial particle (e.g. tobidasu "to fly out, to flee," from tobu "to fly, to jump" + dasu "to put out, to emit").
There are three types of adjective (see Japanese adjectives):
- 形容詞 keiyōshi, or i adjectives, which have a conjugating ending i (い) (such as 暑い atsui "to be hot") which can become past (暑かった atsukatta "it was hot"), or negative (暑くない atsuku nai "it is not hot"). Note that nai is also an i adjective, which can become past (暑くなかった atsuku nakatta "it was not hot").
- 暑い日 atsui hi "a hot day".
- 形容動詞 keiyōdōshi, or na adjectives, which are followed by a form of the copula, usually na. For example, hen (strange)
- 変なひと hen na hito "a strange person".
- 連体詞 rentaishi, also called true adjectives, such as ano "that"
- あの山 ano yama "that mountain".
Both keiyōshi and keiyōdōshi may predicate sentences. For example,
- ご飯が熱い。 Gohan ga atsui. "The rice is hot."
- 彼は変だ。 Kare wa hen da. "He's strange."
Both inflect, though they do not show the full range of conjugation found in true verbs. The rentaishi in Modern Japanese are few in number, and unlike the other words, are limited to directly modifying nouns. They never predicate sentences. Examples include ookina "big", kono "this", iwayuru "so-called" and taishita "amazing".
Both keiyōdōshi and keiyōshi form adverbs, by following with ni in the case of keiyōdōshi:
- 変になる hen ni naru "become strange",
and by changing i to ku in the case of keiyōshi:
- 熱くなる atsuku naru "become hot".
- がga for the nominative case.
- 彼がやった。 Kare gayatta. " He did it."
- にni for the dative case.
- 田中さんにあげて下さい。 Tanaka-san niagete kudasai "Please give it to Mr. Tanaka ."
It is also used for the lative case, indicating a motion to a location.
- 日本に行きたい。 Nihon niikitai "I want to go to Japan ."
- However, へe is more commonly used for the lative case.
- パーティーへ行かないか。 pātī eikanai ka? "Won't you go to the party ?"
- のno for the genitive case, or nominalizing phrases.
- 私のカメラ。 watashi no kamera "mycamera"
- スキーに行くのが好きです。 Sukī-ni ikunoga suki desu "(I) like go ing skiing."
- をo for the accusative case.
- 何を食べますか。 Nani otabemasu ka? " What will (you) eat?"
- はwa for the topic. It can co-exist with the case markers listed above, and it overrides ga and (in most cases) o.
- 私は寿司がいいです。 Watashi wasushi ga ii desu. (literally) " As for me, sushi is good." The nominative marker ga after watashi is hidden under wa.
Note: The subtle difference between wa and ga in Japanese cannot be derived from the English language as such, because the distinction between sentence topic and subject is not made there. While wa indicates the topic, which the rest of the sentence describes or acts upon, it carries the implication that the subject indicated by wa is not unique, or may be part of a larger group.
- Ikeda-sanwayonjū-ni sai da. "As for Mr. Ikeda, he is forty-two years old." Others in the group may also be of that age.
Absence of wa often means the subject is the focus of the sentence.
- Ikeda-sangayonjū-ni sai da. "It is Mr. Ikeda who is forty-two years old." This is a reply to an implicit or explicit question, such as "who in this group is forty-two years old?"
Japanese has an extensive grammatical system to express politeness and formality.
The Japanese language can express differing levels in social status. The differences in social position are determined by a variety of factors including job, age, experience, or even psychological state (e.g., a person asking a favour tends to do so politely). The person in the lower position is expected to use a polite form of speech, whereas the other person might use a plainer form. Strangers will also speak to each other politely. Japanese children rarely use polite speech until they are teens, at which point they are expected to begin speaking in a more adult manner. See uchi-soto.
Whereas teineigo (丁寧語) (polite language) is commonly an inflectional system, sonkeigo (尊敬語) (respectful language) and kenjōgo (謙譲語) (humble language) often employ many special honorific and humble alternate verbs: iku "go" becomes ikimasu in polite form, but is replaced by irassharu in honorific speech and ukagau or mairu in humble speech.
The difference between honorific and humble speech is particularly pronounced in the Japanese language. Humble language is used to talk about oneself or one's own group (company, family) whilst honorific language is mostly used when describing the interlocutor and their group. For example, the -san suffix ("Mr" "Mrs." or "Miss") is an example of honorific language. It is not used to talk about oneself or when talking about someone from one's company to an external person, since the company is the speaker's in-group. When speaking directly to one's superior in one's company or when speaking with other employees within one's company about a superior, a Japanese person will use vocabulary and inflections of the honorific register to refer to the in-group superior and their speech and actions. When speaking to a person from another company (i.e., a member of an out-group), however, a Japanese person will use the plain or the humble register to refer to the speech and actions of their own in-group superiors. In short, the register used in Japanese to refer to the person, speech, or actions of any particular individual varies depending on the relationship (either in-group or out-group) between the speaker and listener, as well as depending on the relative status of the speaker, listener, and third-person referents.
Most nouns in the Japanese language may be made polite by the addition of o- or go- as a prefix. o- is generally used for words of native Japanese origin, whereas go- is affixed to words of Chinese derivation. In some cases, the prefix has become a fixed part of the word, and is included even in regular speech, such as gohan 'cooked rice; meal.' Such a construction often indicates deference to either the item's owner or to the object itself. For example, the word tomodachi 'friend,' would become o-tomodachi when referring to the friend of someone of higher status (though mothers often use this form to refer to their children's friends). On the other hand, a polite speaker may sometimes refer to mizu 'water' as o-mizu in order to show politeness.
Most Japanese people employ politeness to indicate a lack of familiarity. That is, they use polite forms for new acquaintances, but if a relationship becomes more intimate, they no longer use them. This occurs regardless of age, social class, or gender.
There are three main sources of words in the Japanese language, the yamato kotoba (大和言葉) or wago (和語), kango (漢語), and gairaigo (外来語). 
The original language of Japan, or at least the original language of a certain population that was ancestral to a significant portion of the historical and present Japanese nation, was the so-called yamato kotoba (大和言葉 or infrequently 大和詞, i.e. " Yamato words"), which in scholarly contexts is sometimes referred to as wago (和語 or rarely 倭語, i.e. the " Wa language"). In addition to words from this original language, present-day Japanese includes a number of words that were either borrowed from Chinese or constructed from Chinese roots following Chinese patterns. These words, known as kango (漢語 ), entered the language from the 5th century onwards via contact with Chinese culture. According to the Shinsen Kokugo Jiten (新選国語辞典) Japanese dictionary, kango comprise 49.1% of the total vocabulary, wago make up 33.8%, other foreign words or gairaigo (外来語) account for 8.8%, and the remaining 8.3% constitute hybridized words or konshugo (混種語) that draw elements from more than one language.
There are also a great number of words of mimetic origin in Japanese, with Japanese having a rich collection of sound symbolism, both onomatopoeia for physical sounds, and more abstract words. A small number of words have come into Japanese from the Ainu language. Tonakai (reindeer), rakko (sea otter) and shishamo (smelt, a type of fish) are well-known examples of words of Ainu origin.
Words of different origins occupy different registers in Japanese. Like Latin-derived words in English, kango words are typically perceived as somewhat formal or academic compared to equivalent Yamato words. Indeed, it is generally fair to say that an English word derived from Latin/French roots typically corresponds to a Sino-Japanese word in Japanese, whereas a simpler Anglo-Saxon word would best be translated by a Yamato equivalent.
Incorporating vocabulary from European languages, gairaigo, began with borrowings from Portuguese in the 16th century, followed by words from Dutch during Japan's long isolation of the Edo period. With the Meiji Restoration and the reopening of Japan in the 19th century, borrowing occurred from German, French, and English. Today most borrowings are from English.
In the Meiji era, the Japanese also coined many neologisms using Chinese roots and morphology to translate European concepts; these are known as wasei kango (Japanese-made Chinese words). Many of these were then imported into Chinese, Korean, and Vietnamese via their kanji in the late 19th and early 20th centuries. For example, seiji 政治 ("politics"), and kagaku 化学 ("chemistry") are words derived from Chinese roots that were first created and used by the Japanese, and only later borrowed into Chinese and other East Asian languages. As a result, Japanese, Chinese, Korean, and Vietnamese share a large common corpus of vocabulary in the same way a large number of Greek- and Latin-derived words – both inherited or borrowed into European languages, or modern coinages from Greek or Latin roots – are shared among modern European languages – see classical compound.
In the past few decades, wasei-eigo ("made-in-Japan English") has become a prominent phenomenon. Words such as wanpatān ワンパターン (< one + pattern, "to be in a rut", "to have a one-track mind") and sukinshippu スキンシップ (< skin + -ship, "physical contact"), although coined by compounding English roots, are nonsensical in most non-Japanese contexts; exceptions exist in nearby languages such as Korean however, which often use words such as skinship and rimokon (remote control) in the same way as in Japanese.
The popularity of many Japanese cultural exports has made some native Japanese words familiar in English, including futon, haiku, judo, kamikaze, karaoke, karate, ninja, origami, rickshaw (from 人力車 jinrikisha ), samurai, sayonara, Sudoku, sumo, sushi, tsunami, tycoon. See list of English words of Japanese origin for more.
Literacy was introduced to Japan in the form of the Chinese writing system, by way of Baekje before the 5th century.  Using this language, the Japanese king Bu presented a petition to Emperor Shun of Liu Song in AD 478. After the ruin of Baekje, Japan invited scholars from China to learn more of the Chinese writing system. Japanese emperors gave an official rank to Chinese scholars (続守言/薩弘格/ 袁晋卿) and spread the use of Chinese characters from the 7th century to the 8th century.
At first, the Japanese wrote in Classical Chinese, with Japanese names represented by characters used for their meanings and not their sounds. Later, during the 7th century AD, the Chinese-sounding phoneme principle was used to write pure Japanese poetry and prose, but some Japanese words were still written with characters for their meaning and not the original Chinese sound. This is when the history of Japanese as a written language begins in its own right. By this time, the Japanese language was already very distinct from the Ryukyuan languages. 
An example of this mixed style is the Kojiki, which was written in AD 712. They then started to use Chinese characters to write Japanese in a style known as man'yōgana, a syllabic script which used Chinese characters for their sounds in order to transcribe the words of Japanese speech syllable by syllable.
Over time, a writing system evolved. Chinese characters (kanji) were used to write either words borrowed from Chinese, or Japanese words with the same or similar meanings. Chinese characters were also used to write grammatical elements, were simplified, and eventually became two syllabic scripts: hiragana and katakana which were developed based on Manyogana from Baekje.  However this hypothesis "Manyogana from Baekje" is denied by other scholars.  
Hiragana and Katakana were first simplified from Kanji, and Hiragana, emerging somewhere around the 9th century,  was mainly used by women. Hiragana was seen as an informal language, whereas Katakana and Kanji were considered more formal and was typically used by men and in official settings. However, because of hiragana's easy of use, more and more people began using it. Eventually, by the 10th century, hiragana was used by everyone. 
Modern Japanese is written in a mixture of three main systems: kanji, characters of Chinese origin used to represent both Chinese loanwords into Japanese and a number of native Japanese morphemes; and two syllabaries: hiragana and katakana. The Latin script (or romaji in Japanese) is used to a certain extent, such as for imported acronyms and to transcribe Japanese names and in other instances where non-Japanese speakers need to know how to pronounce a word (such as "ramen" at a restaurant). Arabic numerals are much more common than the kanji when used in counting, but kanji numerals are still used in compounds, such as 統一 tōitsu ("unification").
Historically, attempts to limit the number of kanji in use commenced in the mid-19th century, but did not become a matter of government intervention until after Japan's defeat in the Second World War. During the period of post-war occupation (and influenced by the views of some U.S. officials), various schemes including the complete abolition of kanji and exclusive use of rōmaji were considered. The jōyō kanji ("common use kanji", originally called tōyō kanji [kanji for general use]) scheme arose as a compromise solution.
Japanese students begin to learn kanji from their first year at elementary school. A guideline created by the Japanese Ministry of Education, the list of kyōiku kanji ("education kanji", a subset of jōyō kanji ), specifies the 1,006 simple characters a child is to learn by the end of sixth grade. Children continue to study another 1,130 characters in junior high school, covering in total 2,136 jōyō kanji. The official list of jōyō kanji was revised several times, but the total number of officially sanctioned characters remained largely unchanged.
As for kanji for personal names, the circumstances are somewhat complicated. Jōyō kanji and jinmeiyō kanji (an appendix of additional characters for names) are approved for registering personal names. Names containing unapproved characters are denied registration. However, as with the list of jōyō kanji, criteria for inclusion were often arbitrary and led to many common and popular characters being disapproved for use. Under popular pressure and following a court decision holding the exclusion of common characters unlawful, the list of jinmeiyō kanji was substantially extended from 92 in 1951 (the year it was first decreed) to 983 in 2004. Furthermore, families whose names are not on these lists were permitted to continue using the older forms.
Hiragana are used for words without kanji representation, for words no longer written in kanji, and also following kanji to show conjugational endings. Because of the way verbs (and adjectives) in Japanese are conjugated, kanji alone cannot fully convey Japanese tense and mood, as kanji cannot be subject to variation when written without losing its meaning. For this reason, hiragana are suffixed to the ends of kanji to show verb and adjective conjugations. Hiragana used in this way are called okurigana. Hiragana can also be written in a superscript called furigana above or beside a kanji to show the proper reading. This is done to facilitate learning, as well as to clarify particularly old or obscure (or sometimes invented) readings.
Katakana, like hiragana, are a syllabary; katakana are primarily used to write foreign words, plant and animal names, and for emphasis. For example, "Australia" has been adapted as Ōsutoraria (オーストラリア ), and "supermarket" has been adapted and shortened into sūpā (スーパー ).
Study by non-native speakers
Many major universities throughout the world provide Japanese language courses, and a number of secondary and even primary schools worldwide offer courses in the language. This is much changed from before World War II; in 1940, only 65 Americans not of Japanese descent were able to read, write and understand the language. 
International interest in the Japanese language dates from the 19th century but has become more prevalent following Japan's economic bubble of the 1980s and the global popularity of Japanese popular culture (such as anime and video games) since the 1990s. Close to 4 million people studied the language worldwide in 2012: more than 1 million Chinese, 872,000 Indonesian, and 840,000 South Koreans studied Japanese in lower and higher educational institutions. In the three years from 2009 to 2012 the number of students studying Japanese in China increased by 26.5 percent/three years, and by 21.8 percent in Indonesia, but dropped 12.8 percent in South Korea. 
In Japan, more than 90,000 foreign students studied at Japanese universities and Japanese language schools, including 77,000 Chinese and 15,000 South Koreans in 2003. In addition, local governments and some NPO groups provide free Japanese language classes for foreign residents, including Japanese Brazilians and foreigners married to Japanese nationals. In the United Kingdom, study of the Japanese language is supported by the British Association for Japanese Studies. In Ireland, Japanese is offered as a language in the Leaving Certificate in some schools.
The Japanese government provides standardized tests to measure spoken and written comprehension of Japanese for second language learners; the most prominent is the Japanese Language Proficiency Test (JLPT), which features five levels of exams (changed from four levels in 2010), ranging from elementary (N5) to advanced (N1). The JLPT is offered twice a year. The Japanese External Trade Organization JETRO organizes the Business Japanese Proficiency Test which tests the learner's ability to understand Japanese in a business setting. The Japan Kanji Aptitude Testing Foundation, which took over the BJT from JETRO in 2009, announced in August 2010 that the test would be discontinued in 2011 due to financial pressures on the Foundation. However, it has since issued a statement to the effect that the test will continue to be available as a result of support from the Japanese government.  
- Culture of Japan
- Japanese dictionaries
- Japanese exonyms
- Japanese language and computers
- Japanese literature
- Japanese name
- Japanese orthography issues
- Japanese Sign Language family
- Japanese words and words derived from Japanese in other languages at Wiktionary, Wikipedia's sibling project
- Romanization of Japanese
- Shogakukan Progressive Japanese–English Dictionary (book)
- Book of Song 順帝昇明二年，倭王武遣使上表曰：封國偏遠，作藩于外，自昔祖禰，躬擐甲冑，跋渉山川，不遑寧處。東征毛人五十國，西服衆夷六十六國，渡平海北九十五國，王道融泰，廓土遐畿，累葉朝宗，不愆于歳。臣雖下愚，忝胤先緒，驅率所統，歸崇天極，道逕百濟，裝治船舫，而句驪無道，圖欲見吞，掠抄邊隸，虔劉不已，毎致稽滯，以失良風。雖曰進路，或通或不。臣亡考濟實忿寇讎，壅塞天路，控弦百萬，義聲感激，方欲大舉，奄喪父兄，使垂成之功，不獲一簣。居在諒闇，不動兵甲，是以偃息未捷。至今欲練甲治兵，申父兄之志，義士虎賁，文武效功，白刃交前，亦所不顧。若以帝德覆載，摧此強敵，克靖方難，無替前功。竊自假開府儀同三司，其餘咸各假授，以勸忠節。詔除武使持節督倭、新羅、任那、加羅、秦韓六國諸軍事、安東大將軍、倭國王。至齊建元中，及梁武帝時，并來朝貢。
- Nihon shoki Chapter 30:持統五年 九月己巳朔壬申。賜音博士大唐続守言。薩弘恪。書博士百済末士善信、銀人二十両。
- Nihon shoki Chapter 30:持統六年 十二月辛酉朔甲戌。賜音博士続守言。薩弘恪水田人四町
- Shoku Nihongi 宝亀九年 十二月庚寅。玄蕃頭従五位上袁晋卿賜姓清村宿禰。晋卿唐人也。天平七年随我朝使帰朝。時年十八九。学得文選爾雅音。為大学音博士。於後。歴大学頭安房守。