Сколько бы дети ни болтали, бабушка всё равно спокойно режет персики и ставит кефир на стол.

It is a concessive pattern meaning something like:

• No matter how much the children chatter
• However much the children may talk
• Even if the children keep chatting a lot

So the idea is: the children may be talking a lot, but that does not affect бабушка. She still calmly continues what she is doing.

This pattern is very common in Russian:

• сколько бы ... ни ... = no matter how much ...
• как бы ... ни ... = no matter how ...
• где бы ... ни ... = wherever ...
• кто бы ... ни ... = whoever ...

So here the sentence sets up a contrast:
No matter how much the children talk, grandmother still calmly cuts peaches and puts kefir on the table.

This is because бы uses the past form of the verb, but the meaning is often not past at all.

In Russian, the combination:

• verb in past form + бы

can express hypothetical, conditional, or concessive meanings.

So болтали here is not simply they chatted in the past. In this structure, it is part of:

• сколько бы ... ни болтали

which means no matter how much they may chatter / talk.

This is a very important point for English speakers:
the past-form shape after бы does not automatically mean past time.

Examples:

• Что бы он ни говорил... = Whatever he says / may say...
• Куда бы они ни пошли... = Wherever they go...
• Сколько бы мы ни ждали... = No matter how long we wait / may wait...

So here болтали is just the form required by the construction with бы.

They work together in this fixed concessive pattern.

• бы adds a hypothetical/indefinite sense
• ни reinforces the idea of no matter..., whatever..., however...

So:

• сколько дети болтают = how much the children talk
• сколько бы дети ни болтали = no matter how much the children talk

You usually learn this as a single pattern rather than trying to translate each particle literally every time.

Very common models:

• кто бы ни... = whoever
• что бы ни... = whatever
• где бы ни... = wherever
• как бы ни... = however
• сколько бы ни... = no matter how much/how many

So in this sentence, бы and ни are both normal and expected.

Yes. Болтать usually means something like:

• to chatter
• to chat
• to babble
• to talk away

It often suggests casual, nonstop, maybe slightly unimportant talk.

By contrast:

• говорить = to speak / to say / to talk in a more neutral sense

So дети болтают gives a more vivid image of children talking away, chatting noisily, maybe excitedly.

In this sentence, that helps create the contrast with бабушка спокойно режет...
The children are chattering, but grandmother remains calm and continues her task.

Also, болтать is imperfective, which fits ongoing or repeated talking very well.

Всё равно means:

• all the same
• anyway
• still
• it makes no difference

Here it emphasizes that the action in the main clause happens despite the children’s chatter.

So:

• бабушка всё равно спокойно режет персики...

means:

• grandmother still calmly cuts the peaches...
• grandmother calmly goes on cutting the peaches anyway...

It is a very common phrase in Russian.

Examples:

• Я всё равно пойду. = I’m going anyway.
• Он всё равно не слушает. = He still doesn’t listen.
• Что бы ты ни сказал, я всё равно останусь. = Whatever you say, I’m staying anyway.

In this sentence, всё равно strengthens the concessive idea introduced by сколько бы ... ни ....

Спокойно is an adverb meaning:

• calmly
• peacefully
• without agitation

It describes how бабушка performs the actions:

• режет персики
• ставит кефир на стол

So the sense is that while the children may be chattering, grandmother is unbothered and acts in a calm, steady way.

Russian often uses adverbs like this very naturally before the verb:

• спокойно режет
• быстро идёт
• тихо говорит

Here спокойно adds important mood and characterization. It shows not just what she does, but her attitude while doing it.

Персики is the accusative plural of персики / персик in this sentence, because it is the direct object of режет.

She is cutting what?
персики

For inanimate plural nouns, the accusative plural is usually the same as the nominative plural.

So:

• nominative plural: персики
• accusative plural: персики

That is why the form does not visibly change.

Compare:

• Я вижу столы. = I see tables.
• Она режет персики. = She cuts peaches.

But with animate plural nouns, accusative usually matches genitive instead:

• Я вижу студентов. = I see students.

So персики looks unchanged because it is inanimate plural.

Because на стол expresses motion onto the table, while на столе would express location on the table.

Russian distinguishes:

• куда? = to where? → usually accusative
• где? = where? → usually prepositional after на

So:

• ставит кефир на стол = puts kefir onto the table
• кефир стоит на столе = the kefir is standing on the table

This is a very important Russian pattern:

• класть на стол = to put onto the table
• лежать на столе = to lie on the table
• идти в школу = to go to school
• быть в школе = to be at school

So на стол is correct because there is movement to a destination.

Кефир is masculine singular and inanimate. For many masculine inanimate nouns, the accusative singular is the same as the nominative singular.

So:

• nominative: кефир
• accusative: кефир

That is why after ставит you see:

• ставит кефир

Compare:

• Я пью кефир.
• Он купил хлеб.
• Она взяла нож.

All of these are direct objects in the accusative, but the forms look the same as nominative because they are masculine inanimate nouns.

Because the two parts are doing different grammatical jobs.

The subordinate clause:

• Сколько бы дети ни болтали

uses a special concessive pattern meaning no matter how much the children talk / may talk.

The main clause:

• бабушка всё равно спокойно режет персики и ставит кефир на стол

describes what is actually happening in the scene, so the present tense is natural.

This is completely normal in Russian. The subordinate clause is not telling you about real past time; it is just using the form required by the бы construction.

So the sentence combines:

• a general concessive idea in the subordinate clause
• a present-time description in the main clause

English does something similar in meaning, even if the grammar looks different:

• No matter how much the children talk, grandmother still calmly cuts peaches and puts kefir on the table.

Yes, Russian word order is flexible, but the given order is very natural.

Current order:

• Сколько бы дети ни болтали, бабушка всё равно спокойно режет персики и ставит кефир на стол.

This order works well because:

1. the concessive background comes first: no matter how much the children chatter
2. then the main point follows: grandmother still calmly...

This is a common discourse pattern in Russian:
first the circumstance or contrast, then the main action.

Some words here are also placed naturally for emphasis and flow:

• всё равно comes before the verb phrase to stress despite that
• спокойно appears before the verbs to highlight grandmother’s calm manner

You could move things around, but the nuance might shift. For example, moving спокойно later could make it sound slightly more marked or contrastive.

So the sentence as given sounds smooth, idiomatic, and balanced.