Because I said so!
Declaring something is so and so using 「だ」
One of the trickiest part of Japanese is that there is no verb for the state-of-being like the verb "to be" in English. What Japanese has instead, is
a way to declare that something is the way it is by attaching
the hiragana character 「だ」 to a noun or na-adjective only. You'll see what this means
when we learn about nouns and adjectives.
Declaring that something is so using 「だ」
- Attach 「だ」 to the noun or na-adjective
- （１） 。 - Fish.
- （２） だ。 - Is fish.
Seems easy enough. Here's the real kicker though.
| A state-of-being can be implied without using 「だ」! |
As it stands, （１） is simply the word "fish" and doesn't mean anything beyond that. However, we'll see in the next section that with the
topic particle, we can infer that something is a fish from the context without declaring anything.
So the question that should be floating around in your head is, "If you can say something is [X] without using 「だ」,
then what's the point of even having it around?" Well, the main difference is that a declarative statement makes the sentence sound
more emphatic and forceful in order to make it more... well declarative. Therefore, it is more common to hear men use 「だ」 at the end of sentences.
This is also why you cannot use 「だ」 when asking a question because then it sounds like you're making a statement and asking a
question at the same time. (Unless you're declaring a question word such as 「だ」.)
The declarative 「だ」 is also needed in various grammatical structures where a state-of-being must be explicitly declared.
There is also the case where you must not attach it. It's all quite a pain in the butt really but you don't have to worry about it yet.
Conjugating to the negative state-of-being
In Japanese, negative and past tense are all expressed by conjugation. We can conjugate a noun or adjective to either its negative or past tense to
say that something is not [X] or that something was [X]. This may be a bit hard to grasp at first but none of these state-of-being conjugations make
anything declarative like 「だ」 does. We'll learn, in a later lesson, how to make these
tenses declarative by attaching 「だ」 to the end of the sentence .
First, for the negative tense, you simply attach 「じゃない」 to the noun or na-adjective.
Conjugation rules for the negative state-of-being
- Attach 「じゃない」 to the noun or na-adjective
（例） → じゃない (is not friend)
Examples
（１） じゃない。- Is not fish.
（２） じゃない。- Is not student.
（３） じゃない。- Is not quiet.
Conjugating for the past state-of-being
We will now learn the past tense of the state-of-being. To say something was something, 「だった」 is attached to the noun or na-adjective.
In order to say the negative past (was not), the negative tense is conjugated to the negative past tense by simply dropping the 「い」 from 「じゃない」 and adding 「かった」.
Conjugation rules for the past state-of-being
- Past state-of-being: Attach 「だった」 to the noun or na-adjective
（例） → だった (was friend)
- Negative past state-of-being: Conjugate the noun or na-adjective to the negative tense first and then replace 「い」 of
「じゃない」 with 「かった」
（例） → じゃない
→ じゃなかった (was not friend)
（１） だった。- Was fish.
（２） じゃなかった。- Was not student.
（３） じゃなかった。- Was not quiet.
To sum up
We've now learned how to express state-of-being in all four tenses. Next we will learn some particles, which will allow us assign roles to words. Here is a summary chart of the conjugations we learned in this section.
Summary of state-of-being
| Positive | Negative |
|---|
| Non-Past | （だ） | Is fish | じゃない | Is not fish |
|---|
| Past | だった | Was fish | じゃなかった | Was not fish |
|---|
This page has last been revised on 2005/4/7
Removed reference to 「か question marker」 and changed formatting. (2005/4/7)