Learn Hardcore Japanese: sizukana ongaku wo kiku to, watasi ha otitukimasu. - When I listen to quiet music, I calm down.

Na-adjectives take な before a noun:
- 静かな音楽 = quiet music
- きれいな花 = pretty flower
When they come before a noun, you almost always need な.
When they come at the end of the sentence, you use だ / です instead:
- 音楽は静かです。 = The music is quiet.

So:

✅ 静かな音楽
❌ 静か音楽
❌ 静かい音楽 (this mixes na-adjective with i-adjective pattern)

What is the role of the particle を in 音楽を聞く?

を marks the direct object of the verb.

音楽 = music
聞く = to listen (to), to hear

So 音楽を聞く literally means “to listen to music” or “to hear music”, and 音楽 is the thing being listened to, so it takes を.

Pattern:

[object] を [verb]
- ご飯を食べる = eat rice
- 日本語を勉強する = study Japanese
- 音楽を聞く = listen to music

Why is it 聞く and not 聞きます in 静かな音楽を聞くと?

This is because of the conditional use of と.

When you use と to mean “when/whenever/if”, the verb before と is normally in the plain form (dictionary form), not in ます-form:

静かな音楽を聞くと、…
朝起きると、水を飲みます。
春になると、暖かくなります。

The politeness of the whole sentence is decided by the last verb:

静かな音楽を聞くと、私は落ち着きます。 → polite
静かな音楽を聞くと、私は落ち着く。 → plain

So:

Clause before と → plain form
Final verb → choose plain or polite depending on situation

What does と mean in this sentence? Isn’t と usually “and” or a quotation marker?

と has several uses. In this sentence it is a conditional:

静かな音楽を聞くと、私は落ち着きます。
= When / whenever / if I listen to quiet music, I calm down.

Main common uses of と:

A と B = A and B (joining nouns)
- 犬と猫 = dogs and cats
“…と” 思う / 言う = quotation marker
- 「帰ります」と言いました。 = I said “I’m going home.”
X と、Y = when/whenever X happens, Y (an automatic/natural result) happens
- 春になると、暖かくなります。
- ボタンを押すと、ドアが開きます。

In your sentence it’s #3: a natural result:
Listening to quiet music → you (naturally) feel calm.

Why is 私 in the second part: 静かな音楽を聞くと、私は落ち着きます。? Can it be moved or omitted?

Yes, 私 is optional and movable.

Omitting 私 (very common in Japanese):
- 静かな音楽を聞くと、落ち着きます。
  - “When I listen to quiet music, I calm down.”
    The subject “I” is understood from context.
Different positions of 私は are all grammatically fine, with slight emphasis differences:
- 私は静かな音楽を聞くと落ち着きます。
- 静かな音楽を聞くと、私は落ち着きます。

In everyday speech, many people would simply say:

静かな音楽を聞くと落ち着きます。

So 私 just makes the subject explicit; Japanese does not require it if it’s clear from context.

Why is it 私は and not 私が?

は marks the topic (“as for me”), while が marks the subject more tightly.

In this sentence, you’re simply talking about yourself and stating a general tendency:

私は落ち着きます。
→ “As for me, I calm down (in that situation).”

Using が here is grammatically possible but sounds less natural and can give a different nuance, like contrasting with someone else or focusing strongly on who calms down:

静かな音楽を聞くと、私が落ち着きます。
→ Sounds like “When quiet music is played, I (as opposed to others) am the one who calms down.”

For a neutral “I calm down when…” statement, 私は (or omitting “I” entirely) is the most natural choice.

What exactly does 落ち着きます mean here? Is it the same as “relax”?

落ち着く / 落ち着きます literally means “to become calm / to settle down”.

Common meanings:

to calm down (emotionally)
to feel composed, not anxious
to settle (a situation / one’s mind)
to feel at ease in a place

In this sentence:

私は落ち着きます。
= I calm down / I feel calm.

It’s close to “relax”, but リラックスします focuses more on relaxing physically or mentally in a leisurely way, often in a positive, leisurely context.

静かな音楽を聞くと、リラックスします。
= I relax when I listen to quiet music. (feels more like “I can chill out.”)
静かな音楽を聞くと、落ち着きます。
= I calm down when I listen to quiet music. (more about regaining calm / composure)

Is it okay to mix plain and polite forms like this: 聞く (plain) and 落ち着きます (polite)?

Yes, this is normal and correct.

In complex sentences, it’s very common for:

Subordinate clauses (before と, から, ので, けど, etc.) to use the plain form, and
The final verb to decide the overall politeness.

So structures like these are natural:

静かな音楽を聞くと、私は落ち着きます。
忙しいときに電話が来ると、困ります。

If you put 聞きます before と, it sounds off in standard Japanese for this conditional meaning. Use plain form + と, then choose plain or polite for the last verb.

Could I say 静かな音楽を聞いたら、私は落ち着きます instead of 聞くと? What’s the difference?

You can say 静かな音楽を聞いたら、私は落ち着きます, and it’s understandable and natural.

Subtle differences:

〜と
- Often used for whenever / every time and for automatic or natural results.
- Sounds more like a general rule.
- 静かな音楽を聞くと、私は落ち着きます。
  → Whenever I listen to quiet music, I calm down (it naturally has that effect).
〜たら
- Very flexible “when/if” that can be used for one-time events or conditions.
- Slightly more “when that happens (then)…”, not necessarily a rule that always holds.
- 静かな音楽を聞いたら、私は落ち着きます。
  → When I (have) listened to quiet music, I calm down.

For a habitual, reliable effect, 聞くと fits slightly better, but both are acceptable.

I’ve seen 聞く and 聴く for “listen.” For music, shouldn’t it be 聴く?

Both can be used, but there is a nuance:

聞く
- General “to hear / to listen / to ask (a question)”
- Most common and safe in everyday writing.
聴く
- Emphasizes listening carefully / attentively, often to music, concerts, speeches, etc.

So for music:

静かな音楽を聞く → totally fine, very common.
静かな音楽を聴く → slightly more “I am really listening to it,” a bit more literary or expressive.

In textbooks and normal conversation-level writing, 聞く is standard and perfectly correct here.