Learn Hardcore Japanese: yama no kuuki ha sinsen desu.

The particle の links two nouns to show a relationship—much like “’s” or “of” in English.
• 山の空気 literally means “the air of the mountain,” i.e. “mountain air.”

Why is は used after 空気 instead of が?

は marks the topic of the sentence, telling the listener “as for mountain air….”
• Using が would mark 空気 as the subject introducing new or specific information.
• With は, you make a general statement: “As for mountain air, it is fresh.”

Why aren’t there English-style articles like “the” or “a” in Japanese?

Japanese doesn’t have definite or indefinite articles. Context and particles (like は) indicate whether something is specific or general. You simply say 空気 for “air,” and the listener figures out from context.

Why is it 新鮮です and not 新鮮だ?

です is the polite form of the copula; だ is the plain (casual) form.
• Polite: 山の空気は新鮮です。
• Casual: 山の空気は新鮮だ。 or even 山の空気は新鮮。

What kind of adjective is 新鮮, and why isn’t there a な before です?

新鮮 is a な-adjective (形容動詞).
• When it directly modifies a noun, you add な: 新鮮な空気 (“fresh air”).
• When it’s the predicate of a sentence, you attach だ/です without な: 新鮮です.

How do you pronounce 空気, and why are there two vowels in a row?

It’s pronounced くうき (kū-ki), with a long “u” sound.
• In hiragana, the extra う after く indicates vowel lengthening.

Could I say 新鮮な山の空気 instead? What’s the difference?

新鮮な山の空気 is a noun phrase: “fresh mountain air.”
山の空気は新鮮です is a full sentence: “Mountain air is fresh.”
If you wanted to turn the phrase into a sentence, you’d need a copula:
• 新鮮な山の空気です。 (less common than the original word order)

Where is the verb “is” in this sentence?

Japanese uses the copula だ/です instead of a separate “to be” verb. Here, です acts as “is.”

How would you make the sentence negative?

Replace the copula with its negative form:
• Polite negative: 山の空気は新鮮ではありません。
• Casual negative: 山の空気は新鮮じゃない。