Learn Hardcore Russian: Иногда я хочу спрятаться в комнате.

So спрятаться already includes the idea of "myself" in English.
You don’t say спрятать себя here; that would sound unnatural in this context.
Иногда я хочу спрятаться в комнате literally feels like “Sometimes I want to hide (myself) in the room,” but Russian doesn’t need the separate word for “myself” here—the -ся takes care of it.

Why is it спрятаться and not прятаться? What’s the difference?

This is a question of aspect:

прятаться – imperfective, "to be hiding / to hide (in general/habitually)."
спрятаться – perfective, "to hide (once, to complete the action of getting hidden)."

In this sentence:

Иногда я хочу спрятаться в комнате.
→ “Sometimes I want to (go and) hide in the room.”
You imagine the result: being successfully hidden.

If you said:

Иногда я хочу прятаться в комнате.

it would sound more like "Sometimes I want to be in the process of hiding in the room" or "I want to make a habit of hiding there," which is much less natural here.
For a single act you imagine at a given moment, спрятаться (perfective) is the normal choice.

Why is it в комнате and not в комнату?

The preposition в can use two different cases:

Prepositional (где? – where?) → location / place
- в комнате = in the room
Accusative (куда? – where to?) → direction / movement into
- в комнату = into the room

In this sentence, the focus is on being hidden in the room as a place, not on the movement into it, so Russian uses в комнате (prepositional, “in the room”) rather than в комнату (“into the room”).

If you wanted to specify the movement part, you might say:

Иногда я хочу зайти в комнату и спрятаться.
“Sometimes I want to go into the room and hide.”

What case is комнате in, and how is it formed?

Комнате is feminine singular, prepositional case of комната (room).

Declension of комната (singular):

Nominative (кто? что?) – комната (a room)
Genitive (кого? чего?) – комнаты
Dative (кому? чему?) – комнате
Accusative (кого? что?) – комнату
Instrumental (кем? чем?) – комнатой / комнатою
Prepositional (о ком? о чём? где?) – комнате

After в with the meaning “in/inside (where?)”, you use the prepositional → в комнате.

Why is there no word for "a" or "the" before комнате? How do I know if it’s "in a room" or "in the room"?

Russian has no articles (no “a/an” or “the”).
The phrase в комнате can mean:

in a room
in the room
sometimes even in my room, depending on context

The exact English translation depends on what is already known in the conversation:

If we’ve never mentioned this room before → often “in a room.”
If there’s a specific room we both know about → “in the room.”
If we’re talking about the speaker’s own space → English might naturally use “in my room,” even though Russian just says в комнате.

So Russian grammar doesn’t mark this difference; context does.

Could you say Иногда я хочу прятаться в комнате? Would that be wrong?

It’s grammatically correct, but the meaning changes.

спрятаться (perfective): “to hide (once, to achieve the state of being hidden).”
- Иногда я хочу спрятаться в комнате.
  → “Sometimes I feel like going to hide in the room (to end up hidden).”
прятаться (imperfective): “to be hiding / to hide (as an ongoing or repeated activity).”
- Иногда я хочу прятаться в комнате.
  → “Sometimes I want to be hiding in the room / to spend time hiding in the room.”

The second version sounds more like you enjoy the ongoing activity of hiding there, as something repeated or prolonged. In most contexts, the perfective спрятаться is more natural for this sentence.

Can I change the word order? For example: Я иногда хочу спрятаться в комнате or Я хочу иногда спрятаться в комнате?

Yes, Russian word order is flexible, and all of these are possible:

Иногда я хочу спрятаться в комнате.
Neutral; a bit of emphasis on “sometimes” at the beginning.
Я иногда хочу спрятаться в комнате.
Very natural; “sometimes” is lightly attached to я хочу – “I sometimes want…”
Я хочу иногда спрятаться в комнате.
Also possible, but now иногда sounds more directly tied to the act of hiding, e.g. “I want to hide in the room sometimes (not always).” It can feel slightly more specific or nuanced.

All are grammatically correct. The differences are mostly in rhythm and small nuances of emphasis, not in basic meaning.

Do I have to say я? Could I say Иногда хочу спрятаться в комнате?

You can drop я:

Иногда хочу спрятаться в комнате.

Grammatically, it’s fine because the verb form хочу already shows first person singular (“I want”).

However:

In spoken or informal written Russian, dropping я like this sounds stylistic, casual, or emotional (diary style, texting, inner monologue).
In neutral standard speech or writing, including the pronoun (Иногда я хочу…) is more typical and clearer.

So yes, it’s possible, but the original with я is the default neutral style.

Why is it я хочу спрятаться and not something like я хочу, чтобы я спрятался?

In Russian, when you want to say “I want to do X,” the normal pattern is:

хотеть
- infinitive
  → я хочу спрятаться – “I want to hide.”

The чтобы-clause is used when the subject of the two verbs is different, or to express wishes/requests about another person:

Я хочу, чтобы он спрятался в комнате.
“I want him to hide in the room.”

Saying я хочу, чтобы я спрятался is grammatically possible, but sounds overcomplicated and unnatural here. With the same subject (“I” + “I”), infinitive is the standard choice: я хочу спрятаться.

Does Иногда have to be at the beginning of the sentence?

No. Иногда (sometimes) is an adverb and can move around, similar to English “sometimes”:

Иногда я хочу спрятаться в комнате.
Я иногда хочу спрятаться в комнате.
Я хочу иногда спрятаться в комнате.

They’re all correct.

Position affects emphasis and rhythm, not core grammar:

At the start (Иногда…) – stronger emphasis on “sometimes” as a frame.
After я (Я иногда…) – very natural; “I sometimes want…”
After хочу (Я хочу иногда…) – subtly emphasizes that the wanting/hiding is occasional, not constant.

Is спрятаться formal, neutral, or childish? When would you actually use this verb?

Спрятаться is neutral, everyday language. It can be used:

Literally:
- Ребёнок спрятался под стол. – The child hid under the table.
- Он спрятался в ванной. – He hid in the bathroom.
Metaphorically / emotionally:
- Иногда я хочу спрятаться от всех. – Sometimes I want to hide from everyone.

It’s not specifically childish or slangy. You can use it in conversation, in fiction, in informal writing, and even in more serious contexts where “hiding” is the right idea.

Could the sentence mean “Sometimes I want to hide from other people in the room,” or do I need to add something like от всех?

By itself, Иногда я хочу спрятаться в комнате just says:

“Sometimes I want to hide in the room.”

It implies hiding from something/someone, but doesn’t say from whom. If you want to be explicit:

Иногда я хочу спрятаться в комнате от всех.
“Sometimes I want to hide from everyone in the room.”
Иногда я хочу спрятаться в комнате от людей.
“Sometimes I want to hide from people in the room.”

So the original sentence is more general and open-ended; adding от кого? (from whom?) makes it precise.