Мій племінник любить автобуси, а племінниця любить поїзди.

Ukrainian often leaves out a possessive like мій (my) when it is obvious from context or not especially important to repeat it.

So:

• Мій племінник = my nephew
• племінниця = literally niece, but in this sentence it is understood as my niece

You could also say моя племінниця любить поїзди, and that would be perfectly correct. The version in your sentence simply avoids repetition.

Because мій has to match the gender of the noun it describes.

• племінник is masculine, so you use мій
• племінниця is feminine, so if you included my, it would be моя племінниця

Examples:

• мій брат = my brother
• моя сестра = my sister

This is a very common feature in Ukrainian: adjectives and possessive words change form to agree with the noun.

They are a masculine/feminine pair:

• племінник = nephew
• племінниця = niece

Ukrainian often forms related family words this way, with different endings for masculine and feminine nouns.

Here:

• племінник ends in a masculine pattern
• племінниця ends in a feminine pattern

Because both subjects are third person singular:

• Мій племінник = he
• племінниця = she

In the present tense, любить means he/she likes or he/she loves.

So both of these use the same verb form:

• племінник любить
• племінниця любить

Unlike English, Ukrainian does not need separate forms for he likes and she likes in the present tense.

It can mean either likes or loves, depending on context.

The verb is любити. In everyday use, it can express:

• strong affection: love
• general enjoyment or preference: like

In your sentence, since the objects are buses and trains, English would usually translate it as likes rather than loves.

So любить автобуси is best understood as likes buses.

They are plural forms:

• автобус = bus
• автобуси = buses
• поїзд = train
• поїзди = trains

They appear as the direct objects of любить, so a learner might expect a special accusative form. But with inanimate plural nouns, Ukrainian accusative is usually the same as nominative.

So:

• nominative plural: автобуси, поїзди
• accusative plural: also автобуси, поїзди

That is why they look unchanged here.

Yes, Ukrainian does mark direct objects, but the form depends on whether the noun is animate or inanimate.

For inanimate nouns, the accusative often looks the same as the nominative.

That is what happens here:

• автобуси are inanimate
• поїзди are inanimate

So after любить, they stay:

• автобуси
• поїзди

If the objects were animate masculine plural nouns, you would often see a different form.

А often means something like and, while, or but, depending on context.

In this sentence, it connects two contrasting but related statements:

• the nephew likes buses
• the niece likes trains

So а here is something like:

• while
• whereas
• or a mild but

It is not exactly the same as і, which is the more neutral word for and.

Compare:

• і = simple addition
• а = contrast or comparison between two parts

Because in Ukrainian, coordinating conjunctions like а commonly join two clauses, and a comma is normally used before them.

Here you really have two clauses:

• Мій племінник любить автобуси
• а племінниця любить поїзди

So the comma is standard punctuation.

Yes. Ukrainian word order is more flexible than English word order, because endings carry a lot of grammatical information.

The neutral order here is:

• Мій племінник любить автобуси, а племінниця любить поїзди.

But other orders are possible for emphasis, for example:

• Автобуси любить мій племінник, а поїзди любить племінниця.

That would sound more emphatic, highlighting buses and trains.

For learners, the original version is the most natural and safest pattern to use.

The word поїзди is the plural of поїзд.

The letter ї in Ukrainian represents a sound like yi. It also shows that the sound starts a new syllable rather than blending into the previous consonant.

So поїзди is pronounced roughly like:

• po-yiz-DY

A simplified stress guide:

• поїзд → stress on the first syllable: PO-yizd
• поїзди → stress on the last syllable: po-yiz-DY

The ї is important because it signals pronunciation clearly.

Stress is very important in Ukrainian because it is not always predictable. In this sentence, the usual stresses are:

• мій
• племінник
• любить
• автобуси
• племінниця
• любить
• поїзди

A rough guide in English-style marking:

• miy
• pleMINnyk
• LYUbyt
• avtoBUsy
• pleminNYtsya
• LYUbyt
• poizDY

Listening to native audio is especially useful for stress.

Yes, you absolutely could:

• Мій племінник любить автобуси, а моя племінниця любить поїзди.

This is grammatically correct and may sound clearer if you want to emphasize that both are my relatives.

The original version sounds natural too. Omitting the second possessive is common when the meaning is obvious.

So the choice is mostly about style, clarity, and avoiding repetition.

Because Ukrainian usually does not need subject pronouns when the subject is already stated.

The nouns themselves tell you who is doing the action:

• племінник is the subject of the first clause
• племінниця is the subject of the second clause

Also, the verb form любить already shows third person singular.

Ukrainian often leaves out pronouns unless they are needed for emphasis or contrast.