На зустріч прийдуть як тітка, так і дядько.

This is a very common Ukrainian correlative pattern meaning both ... and ....

So:

• як тітка, так і дядько = both the aunt and the uncle

It often adds a slight sense of emphasis, similar to English both X and Y rather than just X and Y.

Compare:

• Прийдуть тітка і дядько. = The aunt and the uncle will come.
• Прийдуть як тітка, так і дядько. = Both the aunt and the uncle will come.

Because together they form a compound subject: тітка + дядько.

Even though each noun is singular on its own, the meaning is plural: two people will come. So the verb must also be plural:

• прийде = will come for one person
• прийдуть = will come for more than one person

So:

• Тітка прийде. = The aunt will come.
• Дядько прийде. = The uncle will come.
• Тітка і дядько прийдуть. = The aunt and the uncle will come.

Because this sentence expresses motion toward an event: someone is coming to the meeting.

With на:

• на зустріч uses the accusative and means to the meeting
• на зустрічі uses the locative and means at the meeting

Compare:

• Вони прийдуть на зустріч. = They will come to the meeting.
• Вони будуть на зустрічі. = They will be at the meeting.

This is a very important distinction in Ukrainian.

Прийдуть is future tense.

It comes from the verb прийти = to come / to arrive. This verb is perfective, so its simple future form means will come.

Forms of the future here include:

• я прийду = I will come
• ти прийдеш
• він / вона прийде
• ми прийдемо
• ви прийдете
• вони прийдуть

So in your sentence:

• На зустріч прийдуть ... = ... will come to the meeting

Ukrainian has no articles, so there is no direct equivalent of the or a/an.

That means:

• тітка can mean an aunt, the aunt, or sometimes simply aunt
• дядько can mean an uncle, the uncle, or sometimes uncle

The exact meaning depends on context.

In this sentence, English often translates naturally with the:

• Both the aunt and the uncle will come to the meeting.

But Ukrainian does not need a separate word for that.

In the construction як ..., так і ..., Ukrainian normally puts a comma before the second part:

• як тітка, так і дядько

So the comma separates the two linked parts of the pair.

This punctuation is standard in Ukrainian writing.

Yes. Ukrainian word order is fairly flexible, although each version may sound slightly different in emphasis.

Your sentence:

• На зустріч прийдуть як тітка, так і дядько.

Other possible orders:

• Як тітка, так і дядько прийдуть на зустріч.
• Як тітка, так і дядько на зустріч прийдуть.

The original version sounds natural and puts the focus first on the meeting and the fact that people will come.

Ukrainian often uses word order to manage emphasis rather than strict grammatical necessity.

Yes, in many cases you can, but the meaning is slightly less emphatic.

Compare:

• На зустріч прийдуть тітка і дядько. = The aunt and the uncle will come.
• На зустріч прийдуть як тітка, так і дядько. = Both the aunt and the uncle will come.

So як ..., так і ... is useful when you want to stress that both people are included.

Yes, дядько is a normal Ukrainian word for uncle.

A few notes:

• дядько is the dictionary form, nominative singular
• in family meaning, it often translates directly as uncle
• it can also sometimes mean a man / mister / older man in other contexts, depending on usage

Here, because it is paired with тітка, the family meaning uncle is clear.

They are in the nominative case, because they are the subject of the sentence.

The people who will come are:

• тітка
• дядько

So they stay in nominative:

• тітка = nominative singular
• дядько = nominative singular

By contrast, зустріч is in the accusative after на because it shows direction toward the meeting.

Then you would use a singular subject and a singular verb:

• На зустріч прийде тітка. = The aunt will come to the meeting.
• На зустріч прийде дядько. = The uncle will come to the meeting.

So the key change is:

• прийде for one person
• прийдуть for more than one person

Usually прийти is closest to come, but in some contexts arrive also works.

In this sentence:

• На зустріч прийдуть ...
• natural English: ... will come to the meeting

But depending on context, English could also say:

• ... will arrive at the meeting

So the Ukrainian verb covers the idea of someone coming to a place, often on foot originally, though in modern use it is much broader.

A rough pronunciation guide:

• На зустріч прийдуть як тітка, так і дядько.
• Na ZOO-strich priy-DOOT yak TEET-ka, tak ee DYAD-ko

A few helpful pronunciation notes:

• зустріч has the stress on the first syllable: ЗУ-стріч
• прийдуть has the stress on the last syllable: прий-ДУТЬ
• тітка has stress on ті
• дядько has stress on дядь

This is only an approximation for English speakers, but it can help you get started.