Кіт нявкає, а собака гавкає і кусає.

In this sentence, а connects two clauses and shows a contrast:

• Кіт нявкає — the cat meows
• а собака гавкає і кусає — while/but the dog barks and bites

So а often means something like and, while, or but, depending on context. Here it feels like while/as for or a mild but: the cat does one thing, and the dog does something different.

If you used і instead, it would sound more like simple addition, with less contrast.

Because а is joining two separate clauses, each with its own subject and verb:

• Кіт нявкає
• собака гавкає і кусає

In Ukrainian, when coordinating clauses like this, a comma before а is normal.

Both are in the nominative singular, because they are the subjects of the sentence.

• кіт = nominative singular
• собака = nominative singular

They are the ones doing the actions:

• the cat meows
• the dog barks and bites

They are all 3rd person singular present tense forms:

• нявкати → нявкає
• гавкати → гавкає
• кусати → кусає

This form is used for he/she/it:

• він/вона/воно нявкає
• він/вона/воно гавкає
• він/вона/воно кусає

Since кіт and собака are singular subjects, the verbs are singular too.

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

So once you say:

• Кіт нявкає
• собака гавкає і кусає

there is no need to add він.

English often requires pronouns, but Ukrainian often leaves them out unless you want emphasis or contrast.

Ukrainian has no articles. There is no direct equivalent of a/an or the.

So:

• кіт can mean a cat or the cat
• собака can mean a dog or the dog

The exact meaning depends on context.

Here і simply means and and joins two verbs with the same subject:

• собака гавкає і кусає

That means:

• the dog barks
• and the dog bites

Ukrainian does not need to repeat собака the second time, because it is understood.

Yes. Ukrainian can leave the object unstated if it is general, obvious, or not important.

So собака ... кусає can mean:

• the dog bites
• the dog is a biting dog
• the dog tends to bite

English can do this too: Dogs bite.

Not completely. Ukrainian word order is fairly flexible, though the neutral order here is very natural:

• Кіт нявкає, а собака гавкає і кусає.

You could change the order for emphasis, but the original sounds straightforward and normal.

For example, moving words around may highlight a different part of the sentence, but for learners, the given order is the best one to copy first.

They can do either, depending on context.

The present tense in Ukrainian can describe:

• something happening right now
• a habit
• a general characteristic

So this sentence could mean:

• the cat is meowing, and the dog is barking and biting right now
• or, more generally, cats meow, and dogs bark and bite

Without more context, both readings are possible.

A rough English-friendly guide is:

• нявкає ≈ NYAV-ka-ye

A few details:

• ня sounds like nya
• вка is pronounced clearly, with the v and k
• є here sounds like ye

So the whole word has three main parts: NYAV-ka-ye.

Yes. They are closely connected to the sounds animals make:

• няв- imitates a cat’s meow
• гав- imitates a dog’s woof/bark

This is very common in Ukrainian animal vocabulary. So these verbs feel quite natural and vivid to native speakers.