Мій дядько народився в березні, а тітка — у квітні.

Народився means was born.

It comes from the verb народитися = to be born. The ending -ся is part of the verb; it often marks a reflexive verb in Ukrainian, but in this case you should mostly learn народитися as the normal dictionary form meaning to be born.

In the sentence:

• Мій дядько народився... = My uncle was born...

Also notice that народився is masculine singular past tense, because дядько is masculine.

If the subject were feminine, you would use:

• тітка народилася = aunt was born

So the full unshortened version would be:

• Мій дядько народився в березні, а тітка народилася у квітні.

Ukrainian often leaves out words that are easy to understand from context.

The full version would be:

• Мій дядько народився в березні, а моя тітка народилася у квітні.

But that sounds more repetitive. So Ukrainian commonly shortens it to:

• Мій дядько народився в березні, а тітка — у квітні.

Here моя is omitted because it is clearly understood that the speaker is still talking about my aunt.

English does the same kind of thing sometimes:

• My uncle was born in March, and my aunt in April.

The dash shows that some words are omitted because they are understood from the first part of the sentence.

So:

• а тітка — у квітні

really means:

• а тітка народилася у квітні
• or more fully: а моя тітка народилася у квітні

This kind of omission is very common in Ukrainian, especially when the repeated verb would be obvious.

So the dash is helping the reader hear the pause and understand that something has been left out.

In this sentence, а means something like and, but with a slight contrast or comparison.

So:

• Мій дядько народився в березні, а тітка — у квітні.

means:

• My uncle was born in March, and my aunt in April.

Why а and not і?

• і = simple and
• а = and / whereas / while, often when comparing two things

Here the speaker is contrasting two different people and two different months, so а sounds very natural.

Because after в or у when talking about in a month, Ukrainian uses the locative case.

Dictionary forms:

• березень = March
• квітень = April

Locative forms:

• в березні = in March
• у квітні = in April

So the month names change form because they are not the subject of the sentence; they come after a preposition meaning in.

They are in the locative case.

After the prepositions в and у, Ukrainian often uses the locative when talking about location or time:

• в березні = in March
• у квітні = in April

This is one of the common uses of the locative: in a month / in a year / in a place.

Usually the meaning is the same here: both can mean in.

The choice between в and у is often made for ease of pronunciation and smoother sound. Ukrainian does this a lot.

So:

• в березні
• у квітні

both mean in.

Why one in the first phrase and the other in the second? Mostly because Ukrainian prefers to avoid awkward clusters of sounds and make the sentence flow better.

In many cases, either form is grammatically possible, but one may sound more natural in context.

In Ukrainian, noun gender is not based only on the last letter.

Дядько means uncle and is a masculine noun, even though it ends in -о.

This is normal for some words referring to male people, for example:

• батько = father
• дядько = uncle

You can tell it is masculine because:

• it refers to a male person
• it takes masculine agreement: мій дядько
• it uses masculine past tense: народився

Because мій must agree with дядько, and дядько is masculine.

So:

• мій дядько = my uncle
• моя тітка = my aunt

The possessive adjective my changes in Ukrainian depending on gender:

• мій for masculine
• моя for feminine
• моє for neuter
• мої for plural

Even though моя is omitted before тітка in this sentence, it is still understood.

Yes.

Because тітка is feminine, the past tense form must also be feminine:

• дядько народився = uncle was born
• тітка народилася = aunt was born

So the full sentence could be:

• Мій дядько народився в березні, а моя тітка народилася у квітні.

The shortened version simply omits the repeated words.

The given word order is natural, but Ukrainian word order is fairly flexible.

Standard version:

• Мій дядько народився в березні, а тітка — у квітні.

You could also say:

• У березні народився мій дядько, а у квітні — тітка.

That can sound more focused on the months.

So the basic meaning stays the same, but changing word order can shift emphasis.

Almost, but in English you would normally say:

• My uncle was born in March, and my aunt in April.
• or My uncle was born in March, and my aunt was born in April.

English usually keeps my before aunt, even when the verb is omitted. Ukrainian is more comfortable dropping both the possessive and the verb when they are obvious from context.

So the Ukrainian sentence is slightly more compact than the most natural English version.

Yes, it is very natural.

Ukrainian commonly uses народитися with months:

• Я народився в травні. = I was born in May.
• Вона народилася у липні. = She was born in July.

And it is also very common to shorten repeated parts of a sentence, just like in your example.

So this sentence sounds normal and idiomatic.