Перерасчёт уже начался.

A careful pronunciation is:

перерасчёт уже начался́
pe-re-ra-SCHYOT u-ZHE na-chal-SYA

A few useful notes:

• ё in перерасчёт is always stressed.
• уже is stressed on the second syllable: ужé.
• начался is stressed on the last syllable: начался́.
• The сч in перерасчёт is pronounced like a long soft shch sound.

So the main stress pattern is:

• перерасчёт
• уже
• начался

Перерасчёт means recalculation or recomputation.

It is often used in formal or administrative contexts, for example:

• recalculation of a bill
• recalculation of wages or payments
• revision of an amount after new information appears

It comes from:

• расчёт = calculation, settlement
• пере- = re-, again

So перерасчёт is literally a calculation done again.

Good question. In Russian, ё is a separate letter, not just a decoration.

So:

• перерасчёт is the fully correct spelling
• in everyday writing, many people write перерасчет
• even if it is written with е, it is still usually pronounced as ё here

For learners, ё is very helpful because it shows both:

• the correct vowel sound
• the stress

In this word, ё tells you immediately that the stress is on the last syllable.

Because перерасчёт is a masculine singular noun.

In the Russian past tense, verbs agree with the subject in:

• gender
• number

So:

• masculine singular: начался
• feminine singular: началась
• neuter singular: началось
• plural: начались

Compare:

• Перерасчёт начался. = The recalculation started.
• Проверка началась. = The inspection started.
• Собрание началось. = The meeting started.
• Работы начались. = The works started / Work began.

Because Russian does not have a separate tense like the English present perfect.

English distinguishes:

• started
• has started

Russian usually uses the past tense for both ideas, depending on context.

So:

• Перерасчёт уже начался.

can mean:

• The recalculation already started
• The recalculation has already started

In natural English, has already started is often the best translation, but in Russian the verb itself is just past tense.

Начался comes from the infinitive начаться.

Compare:

• начать = to start something
• начаться = to begin, to start

This is an important difference:

• Они начали перерасчёт. = They started the recalculation.
  Here someone actively starts it.
• Перерасчёт начался. = The recalculation started / began.
  Here the recalculation itself is the subject.

So -ся is part of the verb начаться, which is the natural verb when the subject is the event itself.

This is about aspect.

• начаться / начался = perfective
• начинаться / начинался = imperfective

In this sentence, the speaker is saying that the start has already happened. That is a completed event boundary, so Russian uses the perfective:

• Перерасчёт уже начался. = The recalculation has already started.

If you used начинался, it would suggest something like:

• it was beginning
• it used to begin
• the process of starting was in progress

That is not the normal choice here.

So the perfective verb is used because the sentence focuses on the fact that the beginning has already occurred.

It is in the nominative case because it is the subject of the sentence.

You can ask:

Что началось? = What started?

Answer:

Перерасчёт.

That shows it is the thing performing the action grammatically, so nominative is the expected case.

Yes, the word order can change, but this version is very neutral:

Перерасчёт уже начался.

Here:

• Перерасчёт = topic/subject
• уже = already
• начался = started/began

You could also say:

• Уже начался перерасчёт.

This is also natural, but it puts a little more attention on already or on the fact that the process has begun.

Russian word order is flexible, but it often changes the emphasis rather than the basic meaning.

Because Russian does not need an auxiliary verb here.

English often uses:

• is starting
• has started

Russian can express the idea with just one verb form:

• начался

So the whole sentence works without any extra word meaning is or has:

• Перерасчёт уже начался.

That is completely normal Russian.

It sounds fairly neutral to formal, mostly because of the noun перерасчёт.

You are likely to hear it in contexts like:

• administration
• utilities
• accounting
• billing
• official notices
• customer service

The grammar itself is not especially formal, but the noun gives the sentence a more official or bureaucratic feel than something very conversational.