Learn Hardcore Japanese: yume ni site ha, totemo genzituteki da to tomodati ni iwaremasita. - For a “dream,” my friend said it’s actually quite realistic.

〜にしては is a fixed pattern that means “for ~ / considering that ~ / for someone/something who is ~” and often implies that the result is unexpected compared to what you’d normally imagine.

So:

夢にしては ≈ “for a dream / considering it’s a dream”
It implies: “Given that it’s only a dream, it’s surprisingly realistic.”

Other examples:

子ども にしては よく頑張った。
= For a child, (he/she) did very well.
初めて にしては 上手ですね。
= Considering it’s your first time, you’re good.

Why is it 夢にしては and not something like 夢には or 夢としては?

These patterns have different functions:

N にしては
→ “for N / considering N”, with a sense of unexpectedness.
- 夢にしてはとても現実的だ。
  = For a dream, it’s very realistic (surprisingly realistic).
N には
→ topic marker (は) attached to に, often “as for N / for N (in some context)”.
- 夢にはいろいろな種類があります。
  = As for dreams, there are various types.
  This doesn’t by itself carry the “unexpected” nuance.
N としては
→ “as N / in the role of N / from the standpoint of N”.
- 夢としては悪くない。
  = As a dream, it’s not bad.
  This speaks more about its role/category, not the “surprisingly X for a dream” feeling.

So 夢にしては is chosen here specifically to give the nuance:
“Surprisingly realistic for a dream.”

Who is actually the subject of this sentence? There is no “I” or “my dream” mentioned.

Japanese often omits subjects when they’re obvious from context.

In this sentence:

夢にしては、　とても　現実的　だ　と　友達　に　言われました。

A natural underlying structure (in English) is:

(I) was told by (a) friend that (my) dream is very realistic for a dream.

So:

The person who has the dream is “I” (私), omitted because it’s obvious the speaker is talking about their own dream.
The topic/subject of 現実的だ is the dream (also understood from context).

You could spell it out like:

私は、自分の夢は、夢にしてはとても現実的だと友達に言われました。
but in natural speech, that’s too heavy, so most of it gets dropped.

Why is there だ before と? What does だと do?

だ is the plain copula (“is / am / are”), and と is the quotation particle.

So 現実的だと literally means:

“(that it) is realistic” (as a quoted clause)

Structure:

現実的だ = “(it) is realistic” (plain form)
〜と言われました = “was told that ~”

Put together:

現実的だと言われました
= “I was told that (it) is realistic.”

In Japanese, when you quote a statement with だ/です, と often comes right after the plain form だ:

うれしいと思う。 = I think (it’s) happy.
学生だと知っている。 = I know (he/she) is a student.
危ないと言われた。 = I was told (it’s) dangerous.

What is the function of と here? Is it the same と as in “and”?

No, this と is not the “and” と; it is the quotation particle.

In 〜だと友達に言われました:

と marks what is being said / thought / heard.
It’s like quotation marks or “that” in English.

Patterns:

〜と言う = say that ~
〜と思う = think that ~
〜と聞く = hear that ~

So:

現実的だと友達に言われました
= I was told (by a friend) that it is realistic.

Why is it 言いました in passive form (言われました) instead of just “my friend said”?

言われました is the passive of 言いました:

言いました = (someone) said
言われました = (I) was told (by someone)

In this sentence, the speaker wants to express:

“I was told by my friend that ~.”

The passive is natural because the focus is on what was said to the speaker, not on what the friend did.

Compare:

友達が「夢にしてはとても現実的だ」と言いました。
= My friend said, “For a dream, it’s very realistic.”
(Focus: the friend speaking)
夢にしてはとても現実的だと友達に言われました。
= I was told (by my friend) that it’s very realistic for a dream.
(Focus: me receiving that comment)

Both are correct, but (2) matches the perspective of the person recounting what was said to them.

Why is 友達 followed by に here? I thought に was “to”, but here it looks like “by”.

You’re seeing に in a passive sentence, where it often marks the agent (“by ~”).

In active voice:

友達が私に言いました。
= My friend said to me.

In passive voice:

私は友達に言われました。
= I was told by my friend.

So:

In active: 〜に often means “to” (direction of the action).
In passive: 〜に often corresponds to “by”, marking who performs the action.

In your sentence:

友達に言われました
= I was told by (a) friend.

Why isn’t there any は or が marking the subject of “is realistic”? Who/what is 現実的だ about?

Japanese frequently omits は/が when the subject is clear from context.

In this sentence:

夢にしては、とても現実的だと友達に言われました。

The implied subject of 現実的だ is “the dream” (my dream). If we make it explicit:

（その夢は）夢にしては、とても現実的だと友達に言われました。
= As for that dream, I was told by a friend that, for a dream, it’s very realistic.

Because:

The whole conversation is about a dream, and
After 夢にしては, it’s obvious that 現実的だ is talking about that dream,

Japanese naturally leaves out その夢は or それは.

What does 現実的 mean exactly? How is it different from just 現実?

現実 (げんじつ) = “reality” (a noun)
現実的 (げんじつてき) = “realistic” (an adjective-like word)

The 〜的 (てき) suffix often turns a noun into an adjectival word meaning “-like / -style / related to ~”.

Examples:

夢（dream）→ 夢的 (not really used)
現実（reality）→ 現実的 = realistic
伝統（tradition）→ 伝統的 = traditional
科学（science）→ 科学的 = scientific

So:

現実 = reality itself
現実的 = having the quality of reality → realistic

In the sentence:

とても現実的だ = “(it) is very realistic.”

Is とても here just “very”? Could I replace it with すごく or かなり?

Yes, とても here means “very” and is a neutral, standard adverb.

You can replace it with other degree adverbs, with slightly different nuance/level of formality:

とても現実的だ
= very realistic (neutral, polite-friendly)
すごく現実的だ
= super/very realistic (more casual, emotional)
かなり現実的だ
= quite / fairly realistic (often feels a bit more measured)
非常に現実的だ
= extremely realistic (formal/written)

So depending on tone:

夢にしては、すごく現実的だね。 (casual)
夢にしては、非常に現実的だと感じました。 (formal)

Could I change the word order, like putting 友達に at the beginning: 友達に、夢にしてはとても現実的だと言われました?

Yes, that sentence is still natural. Japanese word order is relatively flexible as long as:

The quoted clause comes before と.
The verb (here, 言われました) comes at the end.

So these are all natural:

夢にしては、とても現実的だと友達に言われました。
友達に、夢にしてはとても現実的だと言われました。
とても現実的だと、夢にしては友達に言われました。 → a bit odd/stylistic, but grammatical

What you can’t do is break the quoted clause away from と:

✕ と友達に夢にしてはとても現実的だ言われました。
(The quote must stay right before と.)

So, you can move 友達に, 夢にしては, and とても around somewhat, but keep:

[quoted content] + と + 言われました

If I want to be a bit less polite or more casual, how would this sentence change?

To make it more casual, you can:

Change the verb ending from 〜ました (polite) to 〜た (plain).
Optionally add sentence-ending particles like よ, ね, etc.

Examples:

夢にしては、とても現実的だと友達に言われた。
= (plain past)
夢にしては、とても現実的だって友達に言われた。
= using って as a casual quotation marker
夢にしては、とても現実的だって友達に言われたよ。
= adds a soft, explanatory feel

The basic structure and grammar stay the same; only the formality level changes.