Learn Hardcore Japanese: sizukana heya nara, sensei no koe ga kikeru. - In a quiet room, I can hear the teacher's voice.

なら marks a conditional, topic-like frame: “as for/if it’s a quiet room, then ….” It narrows the statement to that condition and often implies contrast with other conditions (e.g., noisy rooms). So it’s not just “if,” but “given that scenario (quiet room), then ….”

Why not use たら/ば/と instead of なら?

They’re all conditionals but differ in nuance:

なら: conditional tied to a given topic or assumption; contrastive; often picks up on what’s just been mentioned.
たら: general “when/if,” event-based and very common.
ば: more formal/abstract or hypothetical; written-ish.
と: automatic result, habitual truth, instructions; can sound too mechanical here. You could say 静かな部屋だったら, but なら nicely highlights the condition “as for quiet rooms.”

Why isn’t there a で after 部屋?

Here 静かな部屋なら sets a condition, not a location. If you want to mark the place explicitly, use:

静かな部屋で(は)先生の声が聞ける (in a quiet room, you can hear…).
To combine both: 静かな部屋でなら、先生の声が聞ける (specifically in the setting of a quiet room).

Is 静かな a special kind of adjective? Why the な?

Yes, 静か is a na-adjective. Before a noun, na-adjectives take な: 静かな部屋. You cannot say 静か部屋 or 静かの部屋.

Could I say 部屋が静かなら instead of 静かな部屋なら?

Yes:

部屋が静かなら… = “if the room is quiet (in that state).”
静かな部屋なら… = “if it’s a quiet type of room / in quiet rooms.” Both are natural; the first frames “quiet” as the room’s state, the second as a noun phrase (“quiet room”).

Why is が used before 聞ける? Shouldn’t it be を?

With the potential form of a transitive verb, the direct object is typically marked by が in standard Japanese:

先生の声が聞ける (standard) In casual speech many natives also say を (e.g., 声を聞ける), but が is safer and preferred in careful writing. With intransitives like 聞こえる, you must use が.

So can I say 先生の声を聞ける?

It’s heard in casual speech and many will accept it, but 先生の声が聞ける is the standard/recommended form. Stick with が on tests and formal writing.

What’s the difference between 聞ける and 聞こえる here?

聞こえる: “be audible; be heard” (involuntary perception). Focus on the sound reaching you. Ex: 先生の声が聞こえる.
聞ける: “can manage to hear; be able to hear; get a chance to hear” (ability/opportunity, sometimes effort or circumstances). Ex: 先生の声が聞ける. In this sentence, 聞こえる would emphasize audibility; 聞ける emphasizes ability/opportunity given the quiet room.

Why can’t I say 先生の声を聞こえる?

聞こえる is intransitive; what “is heard” takes が, not を. Correct: 先生の声が聞こえる.

How is 聞ける formed, and how is it read?

Reading: きける. It’s the potential form of the godan verb 聞く:

Change the final -u to the -e row and add る: 聞く → 聞ける. You can also say 聞くことができる (more formal/explicit).

Who is the subject here? Where is “I/we”?

It’s omitted, which is normal in Japanese. Context supplies it. Default reading is often “I/we/you/people” depending on situation. The sentence states a general ability under the condition.

Can I make the sentence polite?

Yes:

静かな部屋なら、先生の声が聞けます。
More formal: 静かな部屋なら、先生の声を/が聞くことができます。 You can add tone particles: …聞けますよ／ね。

Can I switch が to は in 先生の声が/は?

Yes, with a nuance shift:

先生の声が聞ける: neutral/new-information focus.
先生の声は聞ける: contrastive/topic—“at least the teacher’s voice (can be heard),” possibly implying others can’t.

Does 聞ける ever mean “get the chance to hear” rather than just “be able to hear”?

Yes. 〜が聞ける can mean you have the opportunity to hear something (e.g., 生演奏が聞ける). In your sentence, context could tilt it toward “in a quiet room, you get to hear (i.e., can experience hearing) the teacher’s voice.”

What would a negative/requirement version look like?

Casual: 静かな部屋じゃないと、先生の声は聞けない。
Polite: 静かな部屋でなければ、先生の声は聞けません。 Both mean you need a quiet room; otherwise, you can’t hear it.

Are there other natural rewrites with slightly different nuance?

A few:

静かな部屋では、先生の声が聞こえる。 (location plus audibility)
部屋が静かなら、先生の声が聞こえる／聞ける。 (state-based condition)
静かな部屋でなら、先生の声は聞ける。 (highlighting the specific setting; contrastive)
More formal: 静かな部屋ならば、先生の声が聞ける。

How do I say “only in a quiet room”?

静かな部屋でだけ、先生の声が聞ける。
Or stronger/negative frame: 静かな部屋でしか先生の声は聞けない。

Is 先生の声 the most polite way? What about honorifics?

Neutral is 先生の声. More respectful: 先生のお声. For example: 静かな部屋なら、先生のお声が聞けます。