第9課: Copular Sentences I: Plain Speech

The Japanese language possesses a speech-level hierarchy that determines how one should address any given person based on various factors: relationship, age, role, respect, etc. The social dynamics that set a discourse also shape how said discourse is worded.

Typically, Japanese learners are first introduced to polite speech. This is because polite speech is what is used in most daily interactions; it helps establish courtesy between oneself and those around. As the Japanese learner, the most practical means of using Japanese early on will be centered around speaking to native speakers who are neither family nor close friends. Because the most important use of plain speech involves casual conversation, it is kept to the side until the learner can handle situations where polite speech is imperative.

However, the greatest flaw made by introducing polite speech first lies in the fact that it is not the base form of speech. Within each speech style you will find unique vocabulary, grammar, and endings. Grammatically, plain speech is what makes up the base form of the language. Contrary to its name, plain speech is not limited to conversation among peers or family. In fact, it is grammaticalized in all sorts of grammar points.

Plain speech is also inherently direct, which is why it is heavily used in academic writing. Most importantly, it is what’s used in one’s inner monologue. Plain speech also makes up the heart of most music and literature. The very essence of being able to think in Japanese requires oneself to truly understand the language from the ground up. That cannot be possible if the base is left ignored.

Politeness is an auxiliary element to conversation. Its purpose is not to provide information other than social implications. Strip it away and you get the actual message a sentence is trying to get across. Naturally, plain speech becomes the basis for conjugation, to which politeness is then added.

Vocabulary List


Tera 寺 – Buddhist temple 

Jijitsu 事実 – Fact

Kōmori コウモリ – Bat

Tori 鳥 – Bird

Gakusei 学生 – Student

Kankokujin 韓国人 – Korean

Shodō 書道 – Calligraphy

Geijutsu 芸術 – Art

Baka 馬鹿 – Idiot

Neko 猫 – Cat

Pātii パーティー – Party

Kaishi 開始 – Start/beginning

Dōbutsuen 動物園 – Zoo

Hikiwake 引き分け – A tie

Kawauso カワウソ – Otter

Furansugo フランス語 – French

Gakkō 学校 – School

Seikai 正解 – Correct answer

Wakusei 惑星 – Planet

Meiōsei 冥王星 – Pluto

Ocha お茶 – Tea

Daihyō 代表 – Representative

Gen’in 原因 – Cause

Tabako 煙草・タバコ・たばこ – Tobacco

Kodomo 子供 – Child(ren)

Pen ペン – Pen

Kujira 鯨 – Whale

Sakana 魚 – Fish

Mogi shiken 模擬試験 – Mock exam

Mizu 水 – Water

Jikan 時間 – Time  

Ganjitsu 元日 – New Year’s Day

Getsuyōbi 月曜日 – Monday

Suiyōbi 水曜日 – Wednesday

Kaishibi 開始日 – Start date

Kinō 昨日 – Yesterday

Ashita/asu 明日 – Tomorrow

Yoru 夜 – Night


Watashi 私 – I

Boku 僕 – I (male)

Kare 彼 – He

Kanojo 彼女 – She

Kore これ – This

Sore それ – That

Sono その – That (adj.)

Are あれ – That (over there)

Koko ここ – Here

Kimu キム – Kim

Pikachū ピカチュウ – Pikachu


A – Ah 

The Copular Sentence

The first thing you must learn about Japanese sentence structure is its most basic form: the copular sentence. This is otherwise known as a “noun-predicate” sentence. In other words, “X is Y.” As trivial as it may sound, many far more complex sentences can be broken down to this very structure. First, let’s cover some basic terminology to better understand this topic.

  • SubjectThe person/thing that performs the action or exhibits the description found in the predicate.
  • PredicateThe part of a sentence that gives some information about the subject. 
  • Copula: A word used to link the subject and predicate of a sentence.
  • Noun: In its most basic definition, a word that refers to a person, place, thing, event, substance, or quality. 
  • Auxiliary: An ending that helps construct verbal conjugations.

The predicate of a sentence may take on different forms depending on what the statement is. In the context of this discussion, the copula is the predicate because we are learning how to simply say “X”—the subject—is “Y.” “Y” In this lesson, “Y” will be another noun, which is why “copular sentences” can alternatively be called “noun-predicate sentences.”

In English, the copula verb is “to be,” and it manifests itself in various forms such as “is,” “are,” “was,” “were,” etc. Their use in the English language is profoundly important as they form the basis of a great portion of the statements we make.

i. The dog is a German shepherd.
ii. My husband is a banker.
iii. Apples are fruits.
iv. It was a fossil.
v. A bat is not a bird.

Similarly, Japanese has its own copular verb, which in turn has its own various forms. Before discussing what this all looks like in Japanese, we must first understand what sort of basic conjugations exist in general. Using the English examples i.-v. as a basis, we see that tense and affirmation/negation are major components to a sentence. In English, there are three tenses: past, present, and future. As their names suggest, the past tense refers to an event/state which occurred in the past, the present tense refers to a current event/state, and the future tense refers to an event/state that hasn’t yet realized. Affirmation is positively stating that something is so. Negation is rejecting a premise.

Japanese only has two tenses: non-past and past tense. Unlike English, tense is not so straightforward, but the speaker’s intent is to always make the “time” factor of any statement obvious in context. The non-past tense encompasses both the concepts of the English present tense and future tense. The past tense corresponds to the past tense, but the form that expresses past tense covers a wider semantic scope than the English -ed.

The Copula Da

Putting all this aside, it is now time to familiarize yourself with the base form of the copula in plain speech. This verb is da.  As is the case for any base form of verb, it alone may stand for the non-past tense. As such, da だ can translate as “is,” “are,” or “will be.” Japanese lacks grammatical number, so there is no difference between “is” or “are.”

Because the verb of a Japanese sentence must always be at the end, we can’t simply insert da だ between “X” and “Y.” “X” remains at the start of the sentence, and the sentence ends in “Y da だ.”  To complete the sentence, we will insert the particle wa は in between X and Y. In Lessons 11-12, we’ll learn about the sort of nuances that are expressed with this particle as well as what else can be between X and Y. For now, though, our goal will be to master the basic pattern “X wa は Y da だ.”

Non-past: Present

1. あれはてらだ。
Are wa tera da.
That (over there) is a Buddhist temple.

2. それは(うそ)だ。
Sore wa uso da.
That’s a lie.

3. これは事実(じじつ)だ。
Kore wa jijitsu da.
This is the truth.

4. (わたし)学生(がくせい)だ。
Watashi wa gakusei da.
I’m a student.

5. キムは韓国人(かんこくじん)だ。
Kimu wa kankokujin da.
Kim is Korean.

6. 書道(しょどう)芸術(げいじゅつ)だ。
Shodō wa geijutsu da.
Calligraphy is art.

7. (かれ)馬鹿(ばか)だ。
Kare wa baka da.
He’s an idiot.

Non-Past: Future

8. 元日(がんじつ)月曜日(げつようび)だ。
Ganjitsu wa getsuyōbi da.
New Year’s Day is/will be on Monday.

9. 開始日(かいしび)明日(あした)だ。
Kaishibi wa ashita da.
The start date is/will be tomorrow.

10. パーティーは(よる)だ。
Pātii wa yoru da.
The party will be at night.

Omitting “X”

In Japanese, the subject is often dropped in the sentence. This tends to be the case, especially when the subject is “it.

11. 明日(あした)だ。
Ashita da.
It’s tomorrow.
It’ll be tomorrow.

12. あ、(ねこ)だ!
A, neko da.
Ah, (it’s) a cat!

13. 時間(じかん)だ。
Jikan da.
(It’s) time.

Omitting Da

The copula da だ is also occasionally dropped altogether with a heightened intonation at the end to express various emotions such as anger or surprise. Dropping the copula may also be done in this fashion in English.

14. あ、ピカチュウ(だ)!
A, Pikachū (da)!
Ah, (it’s) Pikachu!

15. 開始(かいし)(だ)!
Kaishi (da)!
Literally: This is the start!

16. 動物園(どうぶつえん)(だ)!
Dōbutsuen (da)!
(It’s) a zoo!

17. ()()け(だ)!
Hikiwake (da)!
(It’s a) draw!

18. あ、カワウソ(だ)!
A, kawauso (da)!
Ah, (it’s) an otter!

Past Tense: Datta だった

To express past tense with the copula da だ, you must conjugate to datta だった. As you learn more, you will see that -TA stands for -ed in anything that conjugates. Remember, Japanese makes no distinctions with grammatical number. This means that “was” and “were” are both expressed with datta だった.

Conjugation Recap

 Non-Past Tense Past Tense
 Da だ Datta だった

19. あれはフランス()だった。
Are wa Furansugo datta.
That was French.

20. ここは学校(がっこう)だった。
Koko wa gakkō datta.
This here was a school.

21. 正解(せいかい)A(エイ)だった。
Seikai wa ei datta.
The correct answer was A.

22. 昨日(きのう)水曜日(すいようび)だった。
Kinō wa suiyōbi datta.
Yesterday was Wednesday.

23. (かれ)子供(こども)だった。
Kare wa kodomo datta.
He was a child.

Grammar Note: The past tense form need not always be interpreted literally. Ex. 23 implies that a male individual happened to be a child and is said as a remember to oneself and/or to others.

Negation: De wa nai ではない

Conjugating da だ into its plain non-past negative form is not as easy as the past tense form. First, you must change da だ to de で. Then, you add wa nai はない. In reality, it’s the nai ない that brings about the negation, which you’ll continue seeing in negative conjugations. Lastly, in conversation, “de wa では” typically contracts to “ja じゃ.”

Conjugation Recap

 Non-Past Tense Past Tense Non-Past Negative
 Da だ Datta だった De wa nai ではない
 Ja nai じゃない

24. これはペンではない。
Kore wa pen de wa nai.
This is not a pen.

25. コウモリはとりではない。
Kōmori wa tori de wa nai.
Bats are not birds.

26. くじらさかなではない。
Kujira wa sakana de wa nai.
Whales are not fish.

27. 冥王星めいおうせい惑星わくせいじゃない。
Meiōsei wa wakusei ja nai.
Pluto isn’t a planet.

28. あれはいぬじゃない。
Are wa inu ja nai.
That isn’t a dog.

29. これはおちゃじゃない。
Kore wa ocha ja nai.
This isn’t tea.

Grammar Note: Saying de nai でない isn’t wrong, but it is typically only seen in literature.

Negative-Past: De wa nakatta ではなかった

The last conjugation we will study in this lesson is the plain negative-past form of the copula. To begin, we start with the negative form from above. We then add -TA to it. When you add -TA to the negative auxiliary -nai ない, you get nakatta なかった. Altogether, this gives you de wa nakatta ではなかった. Just like above, “de wa では” often contracts to “ja じゃ” in conversation, which results in ja nakatta じゃなかった.

Conjugation Recap

 Non-past Past  Negative Negative-Past
 Da だ Datta だったDe wa nai ではない
 Ja nai じゃない
 De wa nakatta ではなかった
Ja nakatta じゃなかった

30. その代表だいひょう彼女かのじょではなかった。
Sono daihyō wa kanojo de wa nakatta.
The representative was not her.
Grammar Note: The demonstrative pronouns briefly mentioned in Lesson 8 actually have adjectival forms. The adjectival form for sore それ is sono その, as demonstrated in Ex. 30. This form often translates to "the" whenever the concepts of "the" and "that" overlap. 

31. 原因げんいん煙草たばこではなかった。
Gen’in wa tabako de wa nakatta.
The cause was not tobacco.

32. あれは模擬試験もぎしけんではなかった。
Are wa mogi shiken de wa nakatta.
That was not a mock exam.

33. かれぼく友達ともだちじゃなかった。
Kare wa boku no tomodachi ja nakatta
He wasn’t my friend.

34. あれはみずじゃなかった。
Are wa mizu ja nakatta.
That wasn’t water.

35. それはうそじゃなかった。
Sore wa uso ja nakatta.
That wasn’t a lie.