inu ha ookii desu.

The dog is big.

Breakdown of inu ha ookii desu.

• は: topic particle
• 犬いぬ: dog
• です: to be
• 大おおきい: big

Questions & Answers about inu ha ookii desu.

What is the role of は in 犬は大きいです?

は is the topic‐marking particle. It tells the listener that 犬 (“dog”) is what we’re talking about. The structure is:
• Topic (犬は) + Comment (大きいです)
So literally: “As for the dog, (it) is big.”

Why is the particle は pronounced wa instead of ha?

Historically, the kana は was pronounced “wa” in certain grammatical functions. In modern Japanese:
• As a particle it’s always read wa.
• Only when it’s part of a regular word (not a particle) is it read ha (e.g. 歯 “tooth” = ha).

Could I use が instead of は (i.e. 犬が大きいです)? What changes?

Yes, 犬が大きいです is grammatically fine, but:

• は marks a general topic or contrast (we’re talking about the dog).
• が highlights the subject or new information (it emphasizes “the dog is big,” perhaps contrasting with other animals).
  Use は for “as for” statements, が when you want to point out or introduce the subject.

How does 大きい function here? Is it a noun or a verb?

大きい is an i-adjective (形容詞). In predicative use (making a statement about the topic), it directly follows the topic and describes it. No extra verb is needed because the adjective itself can act as the predicate.

Why is 大きい placed after 犬は? In English we say “big dog,” with the adjective first.

Japanese sentence structure for statements is:

1. Topic/Subject (with particle)
2. Predicate (verb or adjective)
   Hence 犬は (topic) 大きいです (predicate) = “As for the dog, it is big.”
   When you use an adjective to modify a noun directly (attributive), you do put it before: 大きい犬 = “big dog” (that phrase alone, not a full sentence).

What is です doing in this sentence? Does it mean “is”?

です is the polite copula. It:
• Adds politeness (equivalent to “is” in English polite speech).
• Connects the adjective (大きい) or noun to the topic.
Technically 大きい already functions as a predicate, but です makes it polite.

Can I omit です and still be correct?

Yes. In casual/plain speech you drop です:
• 犬は大きい (plain form) = “The dog is big.”
Use です in formal or polite contexts.

How do I make this sentence negative or past tense politely?

Negative (polite):
• 犬は大きくないです。
• 犬は大きくありません。
Past (polite):
• 犬は大きかったです。
You adjust the adjective’s ending:
• 大きい → 大きくない (negative)
• 大きい → 大きかった (past)

If I want to say just “big dog” (as a noun phrase), how do I do it?

Use the adjective attributively before the noun, without です:
• 大きい犬 = “big dog.”
That phrase modifies 犬 directly.