Learn Hardcore Russian: Я долго выбирал подарок молодым, хотя в приглашении написано, что подарок не обязателен. - I spent a long time choosing a gift for the newlyweds, although the invitation says that a gift is not required.

Я долго выбирал подарок… – focuses on the long process: “I spent a long time choosing a present…”
Я выбрал подарок. – focuses on the result: “I (have) chosen a present.”

With долго (“for a long time”), Russian almost always uses the imperfective to show duration. A natural combination is:

Я долго выбирал подарок и наконец выбрал. – “I spent a long time choosing a present and finally chose one.”

What exactly does молодым mean here, and why is it in the dative case?

Молодым is the dative plural form of молодые (“the young [ones]”). In a wedding context, молодые is a common way to say “the young couple / the newlyweds”.

Dative is used because this is the recipient of the gift:

подарок (кому?) молодым – “a present (to/for whom?) to the young couple.”

Russian often uses the dative to show the indirect object/recipient without any preposition. So English “a present for the couple” becomes simply подарок молодым.

You can also say:

подарок для молодых – gift for the young couple (genitive after для),

but подарок молодым (dative) is more natural when you’re thinking of “a present to give them” rather than just “intended for them” in a general sense.

Could we say молодожёнам instead of молодым? What’s the difference?

Yes:

подарок молодым
подарок молодожёнам

Both mean “a present for the newlyweds”.

Молодые (here used as a noun) is very typical specifically in the wedding context and sounds a bit more colloquial/ceremonial.
Молодожёны is a normal noun meaning “newlyweds” and is slightly more neutral and explicit.

In this sentence, either молодым or молодожёнам would sound natural.

What is написано in в приглашении написано — is it a verb, and why is it neuter?

Написано is the short passive participle of написать (“to write”), neuter singular.

The construction В приглашении написано, что… is an impersonal passive, roughly:

“In the invitation, it is written that…”

There is no explicit subject (“it”) in Russian, so Russian uses a neuter short participle:

В приглашении написано, что…
Там было сказано, что… – “it was said there that…”
На улице холодно. – “It is cold outside.”

The neuter form fits this impersonal pattern where we don’t specify who wrote or said something.

Why is there no word for “is” in подарок не обязателен and в приглашении написано?

In the present tense, Russian usually omits быть (“to be”) in sentences like this.

English: “The gift is not obligatory.”
Russian: Подарок не обязателен.
English: “It is written in the invitation that…”
Russian: В приглашении написано, что…

If you change the tense, быть reappears:

Подарок был обязателен. – The gift was obligatory.
Подарок будет обязателен. – The gift will be obligatory.

Why обязателен and not обязательный in подарок не обязателен?

Обязателен is the short-form adjective; обязательный is the long-form.

Short form (обязателен) is used mainly as a predicate (after an implied “to be”) and often expresses a state or necessity:
- Подарок не обязателен. – “The gift is not required / not obligatory.”
Long form (обязательный) is more like a descriptive label:
- Это обязательный экзамен. – “This is a compulsory exam.”
- Это обязательный платёж. – “This is a mandatory payment.”

Подарок не обязательный would sound like “this gift is not the obligatory kind (as opposed to some other gift)” and is not what the invitation wants to say. Here the short form обязателен is the natural choice.

Can we write подарок необязателен as one word? Is there any difference from не обязателен?

Both are grammatically correct:

Подарок необязателен. – “The gift is optional / not required.”
Here необязателен is a single word meaning “optional”.
Подарок не обязателен. – literally “The gift is not obligatory.”
Separate не can slightly highlight the negation: it is not obligatory (contrary to what you might think).

In practice, both variants can appear in invitations. Необязателен feels a bit more like a fixed dictionary word; не обязателен can sound a bit more contrastive in context, which fits nicely with the хотя… (“although…”) clause.

How flexible is the word order in Я долго выбирал подарок молодым? What changes if we move words around?

Neutral order:

Я долго выбирал подарок молодым.

Common variants and their nuance:

Долго я выбирал подарок молодым. – Emphasizes долго (“It took me a long time…”).
Подарок молодым я долго выбирал. – Emphasizes подарок молодым (“This present for the couple, I spent a long time choosing it.”).
Я подарок молодым долго выбирал. – Also possible; a bit more focus on подарок молодым.

Russian allows word-order changes mainly to shift emphasis or information structure. Completely arbitrary scrambling can sound odd; for instance:

*Я долго молодым выбирал подарок – understandable but feels awkward and not neutral.

How does хотя work here? Does Russian use any special subjunctive form after it?

Хотя is a subordinating conjunction meaning “although / even though”. It is followed by normal indicative verb forms:

…хотя в приглашении написано, что…
“...although it says in the invitation that…”

Russian does not switch to a special subjunctive form after хотя. The verb написано is just a normal past passive form, not a subjunctive.

Be careful not to mix up:

хотя – “although”
хотя бы – “at least”

There is a comma before хотя because it introduces a subordinate clause.

What exactly is the role of что in написано, что подарок не обязателен? Can it be omitted?

Here что is a conjunction meaning “that” and introduces a content (object) clause:

написано, что подарок не обязателен
“(it is) written that the gift is not obligatory.”

Unlike English, Russian normally requires что in this type of clause.
\В приглашении написано, подарок не обязателен* is incorrect.

There is a comma before что because it starts the subordinate clause что подарок не обязателен.

Why is it в приглашении with -ии at the end?

Приглашение ends in -ие. In the prepositional singular, -ие changes to -ии:

приглашение → в приглашении, о приглашении
здание → в здании
задание → в задании

So в приглашении is just the regular prepositional singular form meaning “in the invitation”.

If the speaker is a woman, how would this sentence change?

Only the past-tense verb changes to feminine; everything else stays the same:

Male speaker: Я долго выбирал подарок молодым…
Female speaker: Я долго выбирала подарок молодым…

In the singular past tense, Russian verbs agree with the subject’s gender:

masculine: -л → выбирал
feminine: -ла → выбирала
neuter: -ло (e.g. оно выбрало)