Learn Hardcore Japanese: tomodati no akatyan ga tyuusya wo mite kyuuni nakidasita node, minna de warawaseyou to sita. - When my friend’s baby suddenly started crying after seeing the injection, we all tried to make her laugh.

…it would sound more like you’re setting up “as for my friend’s baby…” as a topic, maybe in contrast with someone else. Here we just want to report what happened, so が is natural.

In short:

が: marks the doer of the action in this specific scene, neutral/new information.
は: topic/contrast; can sound like “as for the friend’s baby…”.

Why is 注射 followed by を? Isn’t 注射 “injection / shot” as a thing, not an action?

Yes, 注射 (ちゅうしゃ) by itself is a noun meaning injection/shot (the thing or the act).

Here it’s the object of the verb 見る (to see), so it takes を:

注射を見て = seeing the injection / when (he) saw the shot

So the structure is:

注射 (thing being seen) + を (object marker) + 見て (te‑form of 見る).

What exactly does the て-form in 見て急に泣き出した mean? Is it “and”, “when”, or “because”?

The て-form can express several relationships. Here it’s a sequential / causal connection:

注射を見て急に泣き出した
- Literally: [He] saw the injection, and suddenly started crying.
- Natural English: When he saw the injection, he suddenly started crying.

So 見て here is close to “on seeing / when (he) saw / after (he) saw”.
It doesn’t strongly say “because”, but in context there is an implied cause-and-effect: seeing the shot → crying.

What’s the nuance of 急に? How is it different from すぐ?

Both relate to time, but they’re different:

急に (きゅうに): suddenly / abruptly
- Focus on how unexpectedly or abruptly something happens.
- 急に泣き出した = suddenly started crying.
すぐ: immediately / right away
- Focus on how soon after something, not whether it was surprising.
- 注射を見てすぐ泣き出した = He started crying right after seeing the shot.

In this sentence, 急に emphasizes the suddenness of the crying, not just the timing.

What does 泣き出した mean exactly, and how is it different from just 泣いた?

泣き出した (なきだした) is:

泣き – verb stem of 泣く (to cry)
出す – auxiliary verb meaning to start doing suddenly / burst out doing
た – past tense

So 泣き出した ≈ suddenly started crying / burst into tears.

Differences:

泣いた: cried (simple past; doesn’t highlight the “starting” moment or suddenness)
泣き始めた: began to cry (more neutral “began”; slightly more formal/neutral)
泣き出した: suddenly started crying / burst out crying (more emotional, sudden, vivid)

In this context, the baby’s reaction is abrupt, so 泣き出した fits well.

What does ので mean here, and how is it different from から?

ので here means “because / so / since”:

…泣き出したので、みんなで笑わせようとした。
→ Because he suddenly started crying, everyone tried to make him laugh.

Nuance:

ので: more polite/soft/objective, often used in narration or polite speech. It can sound like calmly explaining a situation.
から: more direct/subjective, often feels like giving a straightforward reason.

You could say:

泣き出したから、みんなで笑わせようとした。

This is also correct, just a bit more direct/casual. ので is slightly softer and fits a neutral narrative tone.

What does みんなで mean, and why is it で, not は or が?

みんなで means “everyone together / all of us (as a group)”.

Here, で marks a group acting together:

みんなで笑わせようとした
- Literally: tried to make [him] laugh, with everyone (together).
- Naturally: everyone tried to make him laugh.

Compare:

みんなが笑わせようとした。
→ Grammatically OK, but just says “everyone tried to make him laugh,” without clearly emphasizing acting together as a group.
みんなで emphasizes collective action: they all cooperated to cheer up the baby.

So で here is a “as a group / with” marker.

How is 笑わせようとした formed? What are the grammar pieces inside it?

笑わせようとした breaks down like this:

笑う (わらう) – to laugh
笑わせる – causative form: to make/let someone laugh
- Pattern: V‑う → V‑わせる (for many う‑verbs)
笑わせよう – volitional form of 笑わせる: let’s make (him) laugh / try to make (him) laugh / be about to make (him) laugh
- Pattern: ～せる → ～せよう
笑わせようとする – to try to make [someone] laugh / to be about to make [someone] laugh
- とする after the volitional form often = try to V / attempt to V / be on the point of V‑ing
笑わせようとした – past tense of 笑わせようとする
- tried to make [him] laugh / was about to make [him] laugh (attempted).

So the whole clause:

みんなで笑わせようとした = everyone tried to make him laugh.

Why 笑わせようとした and not something like 笑わせようしました?

Because よう is part of the volitional form, and the “try” meaning comes from ～ようとする as a fixed pattern. You don’t attach します directly to ～よう like that.

Correct “try to make (him) laugh”:

笑わせようとした (past)
笑わせようとする (non‑past)

Incorrect:

笑わせようします ❌
笑わせようしました ❌

Think of ～ようとする almost like one unit meaning “try to V / be about to V”, where する is the verb that takes tense:

～ようとした (tried to ~)
～ようとしている (is trying to ~ / is about to ~)

Is 笑わせようとした definitely successful? Does it mean they actually made the baby laugh?

Not necessarily. V‑ようとした often focuses on the attempt or intention, and it can even imply it didn’t fully succeed or was interrupted.

笑わせようとした = they tried / were about to make him laugh
→ no guarantee of success.

If you wanted to clearly express success, you could say something like:

みんなで笑わせてあげた。 – Everyone made him laugh (for his sake).
みんなで笑わせることができた。 – Everyone was able to make him laugh.

In narration, ～ようとした is often used when the emphasis is on the attempt, not the result.

Who is the object of 笑わせようとした? It doesn’t say 赤ちゃんを again.

The red (friend’s) baby is still understood as the object from context.

Japanese often omits pronouns and obvious objects when they’re clear:

Subject: 友達の赤ちゃんが (my friend’s baby)
Everyone reacts to that baby crying
So 笑わせようとした is naturally understood as:
- tried to make *the baby laugh*

If you explicitly say it:

友達の赤ちゃんを笑わせようとした。
→ tried to make my friend’s baby laugh.

Omitting 赤ちゃんを avoids repetition and sounds more natural when the target is obvious.

Could the word order be 友達の赤ちゃんが急に注射を見て泣き出した instead? Does changing the order change the meaning?

Yes, you can say:

友達の赤ちゃんが急に注射を見て泣き出した。

This is still natural. The basic meaning is the same: the baby suddenly started crying when he saw the shot.

Nuance:

注射を見て急に泣き出した
→ Focuses a bit more on: seeing the injection → then suddenly crying.
急に注射を見て泣き出した
→ The 急に can feel like it’s modifying the whole “see and cry” event (suddenly, he saw the shot and started crying), though in everyday speech most listeners won’t over-analyze it.

Both are acceptable; the original order is slightly clearer that the crying is what was sudden.

Could I say 注射を見たら泣き出した instead of 注射を見て泣き出したので? What’s the difference?

You could say:

注射を見たら泣き出した。
→ When he saw the injection, he started crying.

Differences:

見て泣き出した vs 見たら泣き出した
- Vて…: “do X and then Y” / “on doing X, Y happened”; can imply sequence/cause, quite neutral.
- Vたら…: “when/if X happens, then Y happens”; more explicitly a conditional/temporal “when”.
In this context they overlap a lot; both are fine in casual speech.
ので、みんなで笑わせようとした part
- Original: 見て急に泣き出したので、みんなで笑わせようとした。
  → “Because he suddenly started crying when he saw the shot, everyone tried to make him laugh.”
- Using たら you’d need to restructure:
  - 注射を見たら急に泣き出したので、みんなで笑わせようとした。
    This is also possible; it’s like: When he saw the injection, he suddenly began to cry, so everyone tried to make him laugh.

So 見て and 見たら are both plausible, with 見て slightly more neutral/sequential, and 見たら sounding more clearly like “when (he) saw it”.