Хотя мне и не спалось, я всё равно читал книгу.

Because мне не спалось is an impersonal construction.

• я не спал = I wasn’t sleeping / I did not sleep
• мне не спалось = I couldn’t sleep / I just wasn’t able to fall asleep / sleep wouldn’t come

In Russian, this pattern uses:

• the person in the dative case: мне = to me
• the impersonal verb спалось

So the idea is not simply I did not sleep, but more like sleep was not happening for me. It often suggests a state outside the person’s control.

Спалось comes from спаться, which is an impersonal/reflexive verb related to спать (to sleep).

It is commonly used in expressions like:

• Мне хорошо спалось. = I slept well.
• Мне плохо спалось. = I slept badly.
• Мне не спалось. = I couldn’t sleep.

So спалось does not mean simply slept. It means something more like:

• sleep came
• it was possible to sleep
• one was in a condition to sleep

In this sentence, не спалось means the speaker was unable to sleep, probably despite trying.

The и here is a particle that adds emphasis. In this pattern, хотя ... и ... often means:

• although ...
• even though ...

So:

• Хотя мне не спалось... = Although I couldn’t sleep...
• Хотя мне и не спалось... = Although I couldn’t sleep / Even though I couldn’t sleep...

The и is not required in every case, but it is very common after хотя in concessive clauses. It makes the contrast feel a little stronger or more natural.

Yes, both express contrast, but together they sound very natural in Russian.

• хотя introduces the concessive idea: although / even though
• всё равно adds the idea: still / anyway / all the same

So the sentence structure is basically:

• Although X, I still Y.

That combination is extremely common in both Russian and English:

• Хотя было поздно, я всё равно работал.
• Although it was late, I still worked.

So using both is not redundant in a bad way; it is a normal way to emphasize that the second action happened despite the first condition.

Here всё равно means still, anyway, or all the same.

In this sentence:

• я всё равно читал книгу = I still read a book / I was reading a book anyway

It shows that the action happened despite the problem mentioned earlier.

A useful thing to know: всё равно is a very common fixed expression. Depending on context, it can mean:

• still / anyway
  
  • Я всё равно пойду. = I’ll go anyway.
• it makes no difference / it’s all the same
  • Мне всё равно. = I don’t care / It’s all the same to me.

Here it clearly has the first meaning.

Because читал is imperfective, and that fits the meaning here.

• читал = was reading / read (as an activity, process)
• прочитал = finished reading / read through completely

The sentence describes what the speaker was doing during that time: he was reading a book because he couldn’t sleep. The focus is on the ongoing activity, not on finishing the book.

So:

• я читал книгу = I was reading a book / I read a book
• я прочитал книгу = I read the whole book / finished the book

Using прочитал here would change the meaning quite a bit.

Because читать takes a direct object, and direct objects are usually in the accusative in Russian.

• dictionary form: книга
• accusative singular: книгу

So:

• читать книгу = to read a book

This is a standard verb-object pattern.

Because Хотя мне и не spалось is a subordinate clause introduced by хотя.

Russian uses a comma to separate the subordinate clause from the main clause:

• Хотя мне и не спалось, я всё равно читал книгу.

This is similar to English:

• Although I couldn’t sleep, I still read a book.

If the subordinate clause comes first, the comma separates it from the main clause.

Yes, Russian word order is flexible, although some versions sound more natural than others.

The original sentence is very natural:

• Хотя мне и не спалось, я всё равно читал книгу.

Possible variations include:

• Хотя мне и не спалось, я читал книгу всё равно.
• Я всё равно читал книгу, хотя мне и не спалось.

These are grammatically possible, but the original order is the most neutral and natural.

A few points:

• всё равно usually comes before the verb or before the part being emphasized
• putting хотя-clause first makes the contrast especially clear
• moving things around can change emphasis more than basic meaning

They are close, but not identical.

• мне не спалось = I couldn’t sleep / sleep wouldn’t come
• я не мог заснуть = I couldn’t fall asleep

The difference is nuance:

• мне не спалось sounds more like a general sleepless state
• я не мог заснуть focuses more specifically on the failure to fall asleep

So in this sentence, мне не спалось works very well because it describes the speaker’s condition while he was reading.

The correct form here is всё равно.

• всё = all / everything in this fixed expression
• все usually means all (people/things) or everyone, unless the ё is simply omitted in writing

In modern Russian, ё is often omitted in ordinary texts, so you may see:

• все равно

But in this phrase, it is understood as всё равно, not все равно in the everyone sense.

For learners, it is best to remember and write it as всё равно so the meaning is clear.