Japanese is spoken by 130 million people. This makes it the ninth most spoken language by native speakers. Linguists debate over the classification of the Japanese language, and one general theory asserts that Japanese is an isolated language and thus a language family of its own, known as Japonic languages. Another major theory includes Japanese as part of a hypothetical Altaic language family which spans most of Central Asia and would also include Turkic, Mongolic, Tungusic, and Korean languages. Neither of these theories has yet been generally accepted.
Japan is the only country where Japanese is the sole official language (though the island of Angaur has Japanese as one of three official languages). There are, however, numerous speakers in other countries. These are largely due to emigration, most notably to the United States of America (California and Hawaii, in particular), Brazil and the Philippines. Furthermore, when Japan occupied and colonized much of East Asia, Southeast Asia, and the Pacific, the locals were educated in the Japanese language. Many elderly locals in Korea, Taiwan, and parts of China still speak Japanese.
Japan has steadily developed for many centuries and, unlike many other cultures, has not been seriously affected by any major invasions until recent times. A substantial part of the vocabulary, though, has been borrowed over the years from Chinese, Portuguese, Dutch, German, French, and most recently English.
While Japanese grammar is very regular, it is markedly different from English. Japanese is a subject-object-verb (SOV) and topic-prominent language, whereas English is a subject-verb-object (SVO) and subject-prominent language.
To illustrate, the English sentence "Cats eat mice" contains a subject (cats), a verb (eat), and an object (mice), in an SVO order, where the -s is a plural marker, and mouse -> mice is a plural marker by ablaut, but only the word order indicates which is the subject and the object — i.e. which is dining and which is the meal.
The topic-prominence is not obvious in this example; "cat" is the subject (the agent) in English, but it is the topic (what the sentence is about) in Japanese. In the above example, "
The verb kū means "to eat" in an animalistic sense of one animal consuming another. To speak about a person eating, it would make more sense to use the word taberu which means "to eat" as in to consume a meal.
Japanese doesn't have articles to indicate whether the singular, plural, specific or general. In the sentence above, "
Japanese inflects verbs heavily, but nouns very little. This is opposed to English which has very few verb inflections but inflects its nouns more than Japanese. Japanese is, furthermore, a pro-drop language in that it drops pronouns when they are pragmatically inferable. For instance in Japanese one might say "Raining" rather than "It is raining".
Levels of politeness 
Japanese culture and society is based on a hierarchy of higher status (目上 meue) and lower status (目下 meshita). As such, there are three varying levels of politeness. Because Japanese is primarily a "vertical" society, all relationships contain an element of relative station. For example, a student is a lower station than a teacher, and therefore a student would use polite language when speaking to a teacher, but the teacher would use plain language when speaking to a student. A salesperson talking to a customer would place himself far below the customer, and would therefore use honorific language, whereas the customer would use either plain or polite language.
Honorific language is not a separate category from plain and polite language, but a separate concept that uses different rules. When using honorific language, a Japanese speaker modifies nouns, verbs, and adjectives to either lower himself and his associates, or exalt someone else and that individual's associates. Whereas the use of plain or polite language is determined by the relative station of the person to whom you are speaking, the use of honorific language is determined by the relative station of the person about whom you are speaking. Exalted language is applied when you are speaking about someone who is due respect, such as a professor, an executive, a political official, or a customer. Exalted language is only applied to other people, never to oneself. Humble language, however, is only applied to oneself and people associated with oneself. It would be inappropriate, for example, to use humble language to describe a beggar, even though he would be extremely low on the social ladder.
The Japanese writing system 
Japanese is written mostly using three writing scripts, kanji, hiragana and katakana. Kanji are Chinese characters that were first introduced to Japan in the 4th century. Unlike Chinese, Japanese is a highly inflected language with words changing their ending depending on case, number, etc. For this reason, the hiragana and katakana syllabaries were created. The hiragana serve largely to show the inflection of words, as conjunctions and such. The katakana are mainly used for loan-words from other languages.
The Japanese writing system is derived from the Chinese ideographic character set (Japanese: 漢字 kanji, Mandarin: 汉字 hanzi). They are usually very similar to Traditional Chinese characters. Though kanji are Chinese in origin their use is dictated by Japanese grammar. Each character may be read in different ways depending on the context it is in.
The number of existing Chinese characters has been variously estimated at between 40,000 and 80,000; however, only a small subset is commonly used in modern Japanese. An educated Japanese person will generally be able to read between 2,000 and 4,000 characters. In order to be literate in the Japanese language, the student should strive to master at least the 2,136 general-use characters (常用漢字 jōyō kanji) established by the Ministry of Education.
Hiragana and katakana 
The syllabaries, known as kana (
Hiragana and katakana are almost completely phonetic — much more so than the English alphabet. Each set, however, is referred to as a syllabary rather than an alphabet because each character represents an entire syllable with only a single consonant (which is a more recent addition) (see Pronunciation for more). The syllabary charts in Japanese are referred to as the gojūon (
In practical use, hiragana is used to write, for example, inflectional endings for adjectives and verbs (送り仮名 okurigana), grammatical particles (助詞 joshi) and auxiliaries (助動詞 jodōshi), Japanese words that have no kanji (or not commonly known kanji), and annotations to kanji to indicate pronunciation (振り仮名 furigana). Katakana is used to write, for example, foreign words and names, onomatopoeia, emphasized words (somewhat like italicized words in English text), and technical and scientific words, such as plant, animal, and mineral names.