Trying to understand Japanese grammar by translating it into English concepts often leads to confusion. At Japanese from Japan, we believe that learning directly from authentic Japanese materials helps you grasp grammar as native speakers understand it.

This lesson is based on a real worksheet from a Japanese 2nd-grade classroom, showing how simple learning Japanese can be. Japanese has only three basic sentence types, and by learning them today, you’ll be able to form sentences and communicate more effectively.

In this lesson, we'll explore the three types of Japanese sentences, labeled as ア (A), イ (I), and ウ (U):

- ア (A) — "A is B" sentences
- イ (I) — "A has the quality B" sentences
- ウ (U) — "A does B" sentences

1. Group ア (A) — "A is B" Sentences

Structure:

[A] は [B] だ。
[A] wa [B] da.

This sentence type expresses that A is B.

Example:

さめは魚だ。
Same wa sakana da.
A shark is a fish.

Explanation:

- さめ (same) — shark
- は (wa) — topic marker
- 魚 (sakana) — fish
- だ (da) — copula meaning "is"

In this sentence, we're stating that the shark (さめ) is a fish (魚). The copula だ (da) is used to equate A and B. The group letter ア (A) corresponds to the あ (a) sound at the end of だ (da).

2. Group イ (I) — "A has the quality B" Sentences

Structure:

[A] は [adjective]。
[A] wa [adjective].

This sentence type describes A possessing a quality B.

Example:

ありは小さい。
Ari wa chiisai.
An ant is small.

Explanation:

- あり (ari) — ant
- は (wa) — topic marker
- 小さい (chiisai) — small

In this sentence, we're stating that the ant (あり) has the quality of being small (小さい). Adjectives in Japanese often end with the い (i) sound, like 小さい (chiisai). This is why this group is labeled イ (I).

3. Group ウ (U) — "A does B" Sentences

Structure:

[A] が [verb]。
[A] ga [verb].

This sentence type shows that A performs an action.

Example:

ねこが走る。
Neko ga hashiru.
A cat runs.

Explanation:

- ねこ (neko) — cat
- が (ga) — subject marker
- 走る (hashiru) — runs

Here, the cat (ねこ) is performing the action of running (走る). Verbs in their dictionary form in Japanese often end with the う (u) sound, like 走る (hashiru). That's why this group is labeled ウ (U).

Connecting Group Letters to Sounds

- Group ア (A): Ends with だ (da) in "A is B" sentences, which ends with the あ (a) sound.
- Group イ (I): Adjectives end with the い (i) sound in "A has the quality B" sentences.
- Group ウ (U): Verbs end with the う (u) sound in "A does B" sentences.

By remembering the ending sounds, you can easily identify and construct different types of sentences in Japanese.

Practice Exercises

Try forming your own sentences using the structures we've learned.

Exercise 1: "A is B" Sentence (ア (A))

Create a sentence stating that a bird is an animal.

Answer:

鳥は動物だ。
Tori wa doubutsu da.
A bird is an animal.

Explanation:

- 鳥 (tori) — bird
- は (wa) — topic marker
- 動物 (doubutsu) — animal
- だ (da) — copula "is"

Exercise 2: "A has the quality B" Sentence (イ (I))

Form a sentence expressing that the sky is big.

Answer:

空は大きい。
Sora wa ookii.
The sky is big.

Explanation:

- 空 (sora) — sky
- は (wa) — topic marker
- 大きい (ookii) — big

Exercise 3: "A does B" Sentence (ウ (U))

Write a sentence saying that a dog swims.

Answer:

いぬが泳ぐ。
Inu ga oyogu.
A dog swims.

Explanation:

- いぬ (inu) — dog
- が (ga) — subject marker
- 泳ぐ (oyogu) — swims

Conclusion

Congratulations! You've learned the three fundamental types of Japanese sentences:

- "A is B" sentences (Group ア (A)) using だ (da) to equate two nouns. The ending だ ends with the あ (a) sound.
- "A has the quality B" sentences (Group イ (I)) using adjectives ending with the い (i) sound.
- "A does B" sentences (Group ウ (U)) where the verb ends with the う (u) sound.

By understanding these structures and how they correspond to the ending sounds あ (a), い (i), and う (u), you're well on your way to forming basic sentences in Japanese. Keep practicing by creating your own sentences using new vocabulary. Remember, language learning is a journey—enjoy every step of the way!