Learn Hardcore Japanese: ongaku wo kiite, kimoti ga sukosi rakuni narimasita. - After listening to music, I felt a little better.

音楽を聞く = to actively listen to music
音楽が聞こえる = music can be heard / I can hear music (it reaches your ears, not necessarily intentional listening)

In your sentence, you’re clearly doing the action on purpose, so 音楽を聞いて is correct.

Why is it 聞いて and not 聞きました? What does the て-form do here?

聞いて is the て-form of 聞く. The て-form is often used to connect actions or states.

In this sentence:

音楽を聞いて、気持ちが少し楽になりました。
→ Literally: “(I) listened to music, and (my) feelings became a little better.”

Here the て-form:

Connects the first action to the result, and
Often implies a cause or background:
- “After listening to music, my feelings became a little better.”
- or “By listening to music, my feelings became a little better.”

If you said:

音楽を聞きました。気持ちが少し楽になりました。

it would sound more like two separate statements (“I listened to music. My feelings got a bit better.”) with a weaker sense of “because”. The て-form ties them more smoothly and naturally.

Does 聞いて here mean “while listening” or “because I listened”?

The て-form can be a bit flexible. Common readings are:

Sequence: A happened, then B happened
Cause/Reason: Because A, B
Background situation: While A, B

In 音楽を聞いて、気持ちが少し楽になりました。, the natural interpretation for a native speaker is:

Cause/Result or After-effect:
→ “After I listened to music / By listening to music, I felt a bit better.”

“While listening, my feelings became better” is possible contextually, but in everyday understanding this kind of sentence is usually taken as:

“I listened to music, and as a result, I felt better.”

If you really want to emphasize “because”, you can also say:

音楽を聞いて、気持ちが少し楽になりました。 (very natural as-is)
音楽を聞いたので、気持ちが少し楽になりました。
音楽を聞いたから、気持ちが少し楽になりました。

Why is 気持ち marked with が instead of は?

In 気持ちが少し楽になりました, the が marks what became more comfortable: your feelings / state of mind.

気持ち = feelings, mood, emotional state
気持ちが = “(my) feelings (as the subject)”
楽になりました = “became more comfortable/easier/relieved”

So the structure is:

[気持ちが] [楽になりました]
→ “(My) feelings became more comfortable.”

You could add a topic:

私は、音楽を聞いて、気持ちが少し楽になりました。
→ “As for me, after listening to music, my feelings became a little better.”

Here は (私は) sets the topic (“me”), and が marks the specific thing that changed (“my feelings”). This pattern—Topic は + Subject が + なる—is very common.

Using 気持ちは少し楽になりました is also possible, but it slightly shifts the nuance to “as for my feelings, they became better”, often in contrast with something else.

What exactly does 気持ち mean? How is it different from 気分?

気持ち (きもち) is a broad word for:

feelings
emotions
your “heart” / state of mind
how you emotionally feel

In this sentence:

気持ちが少し楽になりました。
→ “My feelings / my heart became a bit lighter / I felt a bit relieved.”

Contrast with 気分 (きぶん):

気分 is more about physical condition or overall mood:
- 気分が悪い = I feel sick / feel unwell
- 気分がいい = I’m in a good mood / feel good (physically or mood-wise)

Rough guide:

Talking about emotional feelings / feelings toward something → 気持ち
Talking about your physical condition or general mood → often 気分

What does 楽に mean, and why is に used?

楽 (らく) is a な-adjective / noun-like adjective that means:

comfortable
easy
less burden / less pain
relieved

Examples:

楽な仕事 = an easy job
もっと楽にしてください。 = Please relax / take it easy.

For な-adjectives plus なる (to become), you use に:

静か + に + なる → 静かになります (become quiet)
元気 + に + なる → 元気になります (become healthy / feel better)
楽 + に + なる → 楽になります (become comfortable / feel relieved)

So:

楽に here is the adverb-like / “to the state of 楽” form.
楽にになりました would be wrong; it must be 楽になりました.

気持ちが少し楽になりました。
→ “My feelings became a little more comfortable / I felt a bit relieved.”

Why is it 楽に and not 楽く, like おいしくなる?

Japanese has two main adjective types:

い-adjectives (end in い)
- e.g. 高い, おいしい, 寒い
- With なる, they change い → く:
  - 高くなる (become expensive)
  - おいしくなる (become tasty)
  - 寒くなる (get cold)
な-adjectives (often behave like nouns + な)
- e.g. 静か, 元気, 楽
- With なる, they take に:
  - 静かになる (become quiet)
  - 元気になる (get well / feel better)
  - 楽になる (become comfortable / easier / relieved)

楽 is a な-adjective, so:

楽くなる ❌ (wrong)
楽になる ✅ (correct)

The に is the normal marker for “becoming [na-adjective]”.

What does なりました add? Why not just say 楽です?

なる means “to become / to get / to turn into” and expresses change.

楽です。
→ “(It / I) am comfortable / It is easy.” (describes the current state)
楽になりました。
→ “(It / I) became comfortable.”
→ “It got easier.”
→ “I came to feel relieved.”

In your sentence:

気持ちが少し楽になりました。
→ “My feelings became a little lighter / I felt a bit better.”

So なりました focuses on the process of changing from “not comfortable” → “more comfortable”.

Grammatically:

なる is a verb, in polite past form: なりました.

Where can 少し go in this sentence, and does the position change the nuance?

Common, natural positions:

気持ちが少し楽になりました。
- This is your sentence.
- Very natural.
- Emphasis is a bit on “the degree of change in comfort”.
少し気持ちが楽になりました。
- Also natural.
- Feels slightly more like “My feelings, a little, became better”—some speakers feel it puts a tiny emphasis on “a little” modifying the whole clause.

Both are acceptable; the nuance difference is subtle in everyday speech.

Avoid:

気持ちが楽に少しなりました。 ❌ (unnatural word order)
気持ち少しが楽になりました。 ❌ (bad particle placement)

Safest and most common patterns:

気持ちが少し楽になりました。
少し気持ちが楽になりました。

Why is there no word for “I” in the sentence?

Japanese often drops the subject (like “I”, “you”, “we”) when it’s clear from context.

In English, we must say “I listened to music and I felt better.”
In Japanese, if it’s obvious that you’re talking about yourself, you just say:
- 音楽を聞いて、気持ちが少し楽になりました。

Listeners will naturally understand it as:

“I listened to music, and (my) feelings became a little better.”

If you really want to spell it out, you can say:

私は音楽を聞いて、気持ちが少し楽になりました。

But in normal conversation, that initial 私は is usually unnecessary unless you’re contrasting with someone else or changing topic.

What level of politeness is 楽になりました, and how would I say this casually?

楽になりました uses the polite past form (なりました = polite past of なる), so the whole sentence is polite:

音楽を聞いて、気持ちが少し楽になりました。
→ Suitable for talking to people you aren’t very close to, or in most normal polite situations.

Casual version (with friends, family, etc.):

音楽を聞いて、気持ちが少し楽になった。

You can also shorten a bit in very casual speech:

音楽聞いて、気持ちちょっと楽になった。
(dropping some particles and using ちょっと instead of 少し)

Can I write 音楽を聴いて instead of 音楽を聞いて? What’s the difference between 聞く and 聴く?

In everyday writing, both 聞く and 聴く are pronounced きく, and both can be used with 音楽.

Nuance:

聞く (common, general-use kanji)
- to hear
- to listen
- to ask (a question)
- Very common and neutral.
聴く (more specialized)
- specifically “to listen carefully / attentively”
- often used for music, speeches, etc., when you’re focusing.

So:

音楽を聞く = listen to music (neutral; perfectly fine)
音楽を聴く = listen attentively to music (slightly more “artistic”/literary feel)

In your sentence, both are acceptable. Most learners start with 聞く, as it’s more common in general.