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TYJ Japanese copula

This article is in the series Teach Yourself Japanese

7.4. Copula

A copula is a word that combines the subject of a sentence and its description. Copulas are often irregular in many languages. The English word be is a copula. It is the verb whose inflexion is most irregular in English. It combines the subject, and its description, such as "Apples are fruits" and "The sky is blue". However, the word is in "The book is on the desk" is not a copula but an existential verb similar to the verb exist.

The plain copula in Japanese is だ "da". It is not a verb but a suffix added to nouns.
Here is an example of the copula:

Romanization:Tô kyô wa syu to da .
Structure:(noun, Tôkyô) (topic marker) (noun, capital) (copula, is)
Meaning:Tôkyô is the capital.

Since the copula, だ "da" is not a verb but a suffix, the combination of the noun しゅと "syuto" and the copula works as if it were a verb. It is important to treat them as a single predicator. You cannot make a pause between the noun and the copula, and you cannot move the noun from the position immediately before the copula. In other words, the copula だ "da" makes a noun work like a verb.

The copula has inflexion like verbs, but it is highly irregular. The past form of だ "da" is だった "datta".

Here is an example of the past form of the copula:

Romanization:Kyô to wa syu to da t ta .
Structure:(noun, Kyôto) (topic marker) (noun, capital) (copula, was)
Meaning:Kyôto was the capital.

Kyôto, a city 400 kilometres west to Tôkyô, was capital of Japan from 794 to 1192.

The polite form of だ "da" is です "desu". Its stem is "des" and the last "-u" is the suffix for the non-past form. Its inflexion is almost the same as the polite suffix ます "masu", and its past form is でした "deshita".

Romanization:Tô kyô wa syu to de su .
Structure:(noun, Tôkyô) (topic marker) (noun, capital) (copula, is + polite)

Romanization:Kyô to wa syu to de si ta .
Structure:(noun, Kyôto) (topic marker) (noun, capital) (copula, was + polite)

The original form of the copula helps us to understand its irregular inflexion. The modern copula だ "da" comes from the old-style copula である "de aru", which is a combination of the word で "de" and the existential verb ある "aru". The word で "de" came from the ancient postposition にて "nite", but now it is considered a form of the copula which uses the existential verb as an auxiliary verb to give tense to a sentence.

Since ある "aru" is a regular Group I verb, its inflection is easy to understand like these:

Romanization:Tô kyô wa syu to de a ru .
Structure:(noun, Tôkyô) (topic marker) (noun, capital) (copula, be) (auxiliary verb, nonpast)

Romanization:Kyô to wa syu to de a t ta .
Structure:(noun, Kyôto) (topic marker) (noun, capital) (copula, be) (auxiliary verb, past)

The old-style copula である "de aru" is scarcely used in spoken Japanese, but it is still often used in written Japanese. Its polite forms are not commonly used even in written Japanese.

To summarize, the modern copula and its polite form are derived as follows:

FormThe original copulaThe contracted copula
de a ru

de a t ta
da t ta
Polite nonpastであります
de a ri ma su
de su
Polite pastでありました
de a ri ma si ta
de si ta
Next article in the series 'Teach Yourself Japanese': Japanese adjectives
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About author
My name is TAKASUGI Shinji. TAKASUGI is my family name, and Shinji is my given name; a family name is placed before a given name in Japan, as in other Asian nations. My family name is capitalized to avoid misunderstanding.

I have been living in Yokohama since I was born. Yokohama is the second largest city in Japan, which is just 30 kilometers away from the biggest city Tôkyô. It takes 30 minutes to go by train from home to Shibuya, which is the hottest town now in Tôkyô.

I work as a display engineer.

One of my hobbies is creating things with computers; creating programs, computer graphics and web pages is the thing I spent a lot of time doing. I am also interested in a wide range of sciences, and linguistics is my favorite. I like English and I like using it, but my focus is mainly on Japanese, which is my native language. I'm proud of knowing the language, and the difference between English and Japanese has been fascinating me. I have been thinking whether I can introduce it to people outside of Japan. My attempt of introducing Japanese with some Java applets has had more than 1 million visitors.


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