kodomo no koro kara no yume ha, syousetuka ni natte sekaizyuu no hito ni yomarerukoto desu.

の is doing two slightly different but related jobs here:

1. 子供のころ

   • 子供 = child
   • ころ = time/period
   • 子供のころ literally = the time of (being) a child → “when I was a child / in my childhood”
     Here の is like the English “of”, linking 子供 (“child”) to ころ (“time”).

2. ころからの夢

   • ころから = from that time / since then
   • 夢 = dream
   • ころからの夢 literally = the dream from that time (on) → “a dream I’ve had since (childhood)”
     Here の links the phrase ころから to 夢, turning “from that time” into an adjective-like phrase modifying 夢.

So:

• First の: 子供
  • ころ → “child time”
• Second の: ころから
  • 夢 → “from-that-time dream”

Both are just connecting words/noun phrases together.

ころ (頃) and 時 can often both mean “when / at the time”.

In this sentence:

• 子供のころ = “when I was a child / in my childhood”.

Nuance differences:

• ころ

  • Slightly softer, more vague: “around that time”, “in those days”.
  • Often used with life stages or approximate times:
    • 学生のころ – when I was a student
    • 小さいころ – when I was little

• 時

  • Feels a bit more neutral/precise: “at the time when …”.
  • Very common in structures like:
    • 子供の時 – when I was a child
    • 日本にいる時 – when I am in Japan

In this sentence, 子供のころ and 子供の時 would both be grammatical and understandable; 子供のころ just sounds slightly more like “back in my childhood” rather than a sharply defined time.

から here means “from / since” in a temporal sense:

• 子供のころ = when I was a child
• 子供のころから = from when I was a child / since childhood

Then that whole phrase gets linked to 夢 by の:

• 子供のころからの夢 = “a dream (I’ve had) since childhood”.

So ころ → “time”, から → “from that time”, and の → connects that entire idea to 夢.

Japanese often uses topic–comment structure:

• 夢は – “As for (my) dream, …”
• … です – “… is …”

Key points:

• は marks 夢 as the topic, not necessarily the grammatical subject.
• The subject “I” is understood from context and omitted:
  • Full but less natural: 私の子供のころからの夢は … です。
  • Natural Japanese: omit 私の because it’s obvious from the situation.

So the structure is:

• (私の)子供のころからの夢は = As for (my) dream since I was a child,
• …ことです。 = it is (to…)

This mirrors English like:
“As for my childhood dream, it is to become a novelist and be read by people all over the world.”

The pattern A に なる means “to become A”.

• 小説家 = novelist
• 小説家に なる = to become a novelist

Here, に marks the resulting state or role you change into.

Compare:

• 医者に なる – become a doctor
• 先生に なる – become a teacher

Without に, 小説家なる would be ungrammatical. You need に to express “become X”.

なって is the て-form of なる. The て-form is often used to:

• Link actions in a sequence, like “… and then …”
• Join related actions done by the same person.

So:

• 小説家に なって – become a novelist and (then) …
• 世界中の人に 読まれる – be read by people all over the world

Together:

• 小説家になって 世界中の人に 読まれる
  → “become a novelist and be read by people all over the world”

Both actions share the same (implied) subject: I.
The て-form smoothly connects these two parts into one dream: not just to become a novelist, but to become one and be widely read.

読む = to read (active)
読まれる = to be read (passive)

The dream is not “to read people all over the world” but “to be read by people all over the world.” That’s why the passive is used.

• 世界中の人に 読まれる
  
  • Literally: “to be read by people all over the world”
  • 人に = by people (agent of the passive)
  • 読まれる = is read

So the passive matches the natural English idea “to be read (by someone)”.

Breakdown:

• 世界中 = the whole world / all over the world
• 世界中の 人 = people of the whole world → “people all over the world”
  
  • の links 世界中 to 人, making “worldwide” describe the people.
• 世界中の人に 読まれる
  
  • 人に = by people (in the passive construction)
  • に marks the agent of the passive verb 読まれる.

So literally:

• 世界中の人に 読まれる = “to be read by people of the whole world.”

You can’t say 読まれるです; verbs don’t directly attach to です in that way.

こと turns a verb phrase into a noun-like concept (a nominalizer):

• 読まれる – “(to) be read” (verb phrase)
• 読まれること – “the act/state of being read” / “being read” (as a thing)

Then you can say:

• … は 読まれることです。
  = “… is being-read (as a concept).”

In this sentence:

• 子供のころからの夢は – My dream since childhood (topic)
• 小説家になって 世界中の人に 読まれることです。
  – is: to become a novelist and be read by people all over the world.

So こと is necessary to turn “become a novelist and be read…” into a noun phrase that can be equated with 夢 via です.

Both は and が can mark nouns, but their roles differ:

• は marks the topic (“as for X…”)
• が usually marks the subject (who/what actually does/is something in the clause)

Here, we’re introducing 夢 as the topic and then explaining what that dream is:

• 夢は … ことです
  = As for (my) dream, it is …

If you said 夢が … ことです, it would sound odd because が would try to make 夢 the grammatical subject of …ことです, but こと is actually the thing being described by です.

Natural patterns are:

• 私の夢は ～ことです。 – My dream is to ~.
• Or: ～ことが 夢です。 – Doing/being ~ is (my) dream.

So:

• 夢は … ことです。 – topic: dream
• …ことが 夢です。 – subject: “doing/being …”

Japanese often omits obvious subjects and possessors.

From context, a sentence like:

• 子供のころからの夢は、…です。

will be understood as:

• (私の)子供のころからの夢は、…です。
  → “My dream since I was a child is …”

We infer 私 because:

• People usually talk about their own dreams.
• No other person has been mentioned.
• Japanese relies heavily on context instead of repeating “I/my”.

You could explicitly say:

• 私の子供のころからの夢は、小説家になって…です。
  But in natural conversation or writing, omitting 私の is very common.

Yes, several variations are possible, with small nuance differences:

1. 私の子供のころからの夢は、小説家になって世界中の人に読まれることです。

   • Adds 私の, making it explicit: my dream. Slightly more formal/explicit.

2. 子供のころからの夢は、小説家になり、世界中の人に読まれることです。

   • Uses なり、 instead of なって.
   • Feels a bit more formal/literary than the te-form.

3. 子供のころからの夢は、小説家になって、世界中の人に読まれることでした。

   • でした (past) → “was my dream since childhood.”
   • Implies that this may no longer be the dream now.

4. 小説家になって世界中の人に読まれることが、子供のころからの夢です。

   • Flips the order:
     “To become a novelist and be read by people all over the world is my dream since childhood.”
   • Focus is a bit more on the content of the dream (the こと) rather than on 夢 as a topic.

All of them are grammatically correct; the original is a clear, natural, standard way to say it.