Даже если вода прохладная, дочка всё равно хочет плескаться и нырять вместе с братом.

This is a very common Russian pattern:

• даже если = even if
• всё равно = still / anyway

Together they create the idea:

• Even if the water is cool, the daughter still wants...

Russian often likes this double marking of contrast. In English, we can say either:

• Even if the water is cool, she still wants to...
• or simply Even if the water is cool, she wants to...

In Russian, adding всё равно sounds very natural and emphasizes that the result does not change.

Yes, it could:

• Даже если вода прохладная, дочка хочет плескаться и нырять вместе с братом.

This is grammatical, but всё равно adds emphasis: she wants to do it despite that fact.

So:

• without всё равно = neutral
• with всё равно = more explicit contrast, closer to still / anyway

No, not quite.

• если = if
• даже если = even if

Compare:

• Если вода прохладная, дочка не купается.
  If the water is cool, the daughter doesn’t swim.
  This is a normal condition.

• Даже если вода прохладная, дочка всё равно хочет плескаться.
  Even if the water is cool, she still wants to splash around.
  Here the condition does not stop her.

So даже если introduces a stronger concessive idea: the following fact is true in spite of that condition.

Because прохладная is an adjective agreeing with вода.

• вода is feminine singular
• so the adjective must also be feminine singular:
  • прохладная

This is a normal Russian predicate structure:

• Вода прохладная. = The water is cool.

By contrast, прохладно is not used as an agreeing adjective here. It is more like cool in an impersonal sense:

• Здесь прохладно. = It’s cool here.

So:

• вода прохладная = the water is cool
• здесь прохладно = it is cool here

Not exactly.

• прохладная = cool, pleasantly or mildly cold
• холодная = cold

So прохладная вода suggests water that is a bit chilly, but not necessarily unpleasantly cold. It fits well in a sentence where someone still wants to play in it.

If the sentence used холодная, it would sound stronger:

• Даже если вода холодная... = Even if the water is cold...

That suggests more resistance to the idea.

Both mean daughter, but the tone is different.

• дочь = the basic, neutral word
• дочка = a more affectionate, everyday form

In many family contexts, Russian often uses дочка, сынок, мама, папа, etc., especially in warm or informal speech.

So here дочка sounds natural and slightly affectionate, like how a parent might refer to their child.

Russian does not use a separate word like English to before infinitives in this kind of structure.

After хотеть (to want), Russian simply uses the infinitive directly:

• хочет плескаться
• хочет нырять

So:

• она хочет читать = she wants to read
• он хочет спать = he wants to sleep

The infinitive form itself already carries the meaning of English to + verb.

Because the sentence describes activities in a general, ongoing, or repeated sense, not single completed actions.

• плескаться = to splash around / play in the water
• нырять = to dive, to keep diving, to dive as an activity

Imperfective verbs are very common after хотеть when talking about enjoying, doing, or engaging in activities in general.

Here the meaning is something like:

• she wants to be splashing around and diving
• she wants to do those activities

If you used perfective forms, it would sound more like wanting to perform one completed action.

Плескаться is a reflexive verb connected with water. It often means:

• to splash around
• to paddle around
• to frolic in the water

It does not just mean making one splash. It suggests playful movement in water, especially by children.

So in this sentence, плескаться gives a lively, playful image.

The -ся ending marks a reflexive verb. But reflexive verbs in Russian are not always literally reflexive in the English sense.

Here плескаться does not mean to splash oneself in a strict word-for-word way. It is just the standard dictionary form for splash around / splash about.

Many Russian verbs with -ся develop meanings that are best learned as whole vocabulary items. So it is best to remember:

• плескать = to splash something
• плескаться = to splash around, especially in water

Because the preposition с meaning with takes the instrumental case.

So:

• брат = nominative
• с братом = with the brother / with her brother

And вместе с is a very common phrase meaning together with.

Examples:

• с мамой = with mom
• с другом = with a friend
• вместе с братом = together with her brother

So братом is instrumental singular.

Because с братом is the normal form here.

Russian sometimes uses со instead of с for easier pronunciation, especially before difficult consonant clusters, for example:

• со мной = with me
• со всеми = with everyone

But with братом, simple с is easy to pronounce, so:

• с братом is standard

Yes. Russian often leaves that kind of possession implied by context.

Since the sentence already says дочка and refers to a family situation, с братом naturally means with her brother.

Russian does this a lot when the relationship is obvious from context.

English often requires:

• with her brother

Russian often simply says:

• с братом

Yes, Russian word order is flexible.

The version in the sentence is very natural:

• дочка всё равно хочет...

But you could also hear:

• дочка хочет всё равно плескаться...
• всё равно дочка хочет...

These are not all equally neutral, though. Word order in Russian often affects emphasis rather than basic grammar.

The given order is probably the most straightforward for this sentence:

• topic: дочка
• contrast/emphasis: всё равно
• main verb: хочет

Because the sentence begins with a subordinate clause:

• Даже если вода прохладная = subordinate clause
• дочка всё равно хочет... = main clause

Russian uses a comma to separate these clauses.

This is similar to English:

• Even if the water is cool, the daughter still wants...

So the comma is required.

Yes. A common alternative is:

• Хотя вода прохладная, дочка всё равно хочет плескаться... = Although the water is cool, the daughter still wants to splash around...

Another is:

• Несмотря на то, что вода прохладная, дочка всё равно хочет... = Despite the fact that the water is cool...

These are close in meaning, but the feel is slightly different:

• даже если = even if
• хотя = although
• несмотря на то, что = despite the fact that

The original sentence has a nice natural spoken feel.

It can be understood either way, depending on context, but it most naturally sounds like a general tendency or a typical situation.

That is because of:

• the imperfective verbs плескаться and нырять
• the broad descriptive style

It suggests:

• whenever the water is a bit cool, she still wants to play in it

But in the right context, it could also describe one particular moment.

Because Russian often omits pronouns when the noun is already present or the subject is clear.

Here the subject is explicitly named:

• дочка

So adding она would be unnecessary.

Russian generally avoids repeating subject pronouns when they are not needed.

Its core meaning is to dive or to go under the water.

So it usually suggests actual submerging, not just entering the water.

Depending on context, it can refer to:

• diving underwater repeatedly
• ducking under the water
• swimming and diving as a fun activity

In this sentence, paired with плескаться, it sounds playful and childlike.

Вода is in the nominative case because it is the subject of the clause:

• вода прохладная = the water is cool

The adjective прохладная also stays in nominative feminine singular to agree with вода.

So:

• вода = nominative singular
• прохладная = nominative singular feminine adjective

Because дочка is the subject of the main clause:

• дочка хочет... = the daughter wants...

So both clauses have their own subject:

• вода in the first clause
• дочка in the second clause

Both are therefore in the nominative case.