Na stole je sklenice s marmeládou z borůvek.

Because na can take two different cases depending on meaning:

• na + locative = location, on
• na + accusative = movement toward a surface, onto

Here the jar is already sitting there, so Czech uses the locative:

• na stole = on the table

Compare:

• Je to na stole. = It is on the table.
• Polož to na stůl. = Put it onto the table.

Also note the noun change:

• dictionary form: stůl = table
• locative singular: stole

So na stole is the normal form for on the table.

Because the grammatical subject is sklenice, which is singular.

• sklenice = a glass / jar
• je = is

Even though borůvek is plural in English sense (blueberries), that is not the subject of the sentence. It is just part of the phrase z borůvek = from blueberries.

So the core structure is:

• Na stole je sklenice. = There is a jar on the table.

That is why Czech uses je, not jsou.

It is nominative singular, because it is the subject of the sentence.

In Czech, after je in a sentence like this, the thing that exists or is located somewhere is usually in the nominative:

• Na stole je sklenice.
• V pokoji je židle.
• Na zdi je obraz.

So here:

• sklenice = nominative singular

Its basic dictionary form is also sklenice, so there is no visible ending change.

It can mean either, depending on context.

Common meanings of sklenice include:

• a drinking glass
• a glass container, often a jar

In this sentence, because it contains jam, English would usually say:

• a jar of blueberry jam

Literally, though, Czech says something more like:

• a glass/jar with jam made from blueberries

So sklenice is natural Czech, even if English prefers jar in this context.

Because the preposition s meaning with requires the instrumental case.

The base noun is:

• marmeláda = jam / marmalade

In the instrumental singular, it becomes:

• marmeládou

So:

• s marmeládou = with jam

This is a very common pattern:

• s kamarádem = with a friend
• s knihou = with a book
• s vodou = with water

So the ending -ou here is a normal feminine instrumental singular ending.

Because z meaning from / out of / made from takes the genitive case.

The base noun is:

• borůvka = blueberry / bilberry

Here it is plural and in the genitive:

• borůvek

So:

• z borůvek = from blueberries

This phrase tells you what the jam is made of.

A useful pattern:

• džus z pomerančů = juice from oranges
• víno z hroznů = wine from grapes
• marmeláda z borůvek = jam from blueberries

The form borůvek may look irregular at first, but it is the standard genitive plural form.

Yes. Both are natural, but they sound a little different in structure.

You can say:

• marmeláda z borůvek = jam made from blueberries
• borůvková marmeláda = blueberry jam

The second version uses an adjective:

• borůvková = blueberry

So a very natural alternative sentence would be:

• Na stole je sklenice s borůvkovou marmeládou.

That version still uses the instrumental after s, so:

• borůvková marmeláda becomes s borůvkovou marmeládou

Both versions are good. The original sentence is slightly more literal in how it describes the jam.

Because Czech word order is flexible, and the beginning of the sentence often gives the setting or known information first.

So:

• Na stole je sklenice s marmeládou z borůvek.

feels like:

• On the table, there is a jar of blueberry jam.

This is very natural if the speaker wants to first say where something is.

A different word order is also possible:

• Sklenice s marmeládou z borůvek je na stole.

That sounds more like:

• The jar of blueberry jam is on the table.

So the choice of word order affects emphasis more than basic meaning.

Because Czech has no articles.

Unlike English, Czech does not normally use separate words for a/an or the. Whether something is definite or indefinite is understood from context, word order, and the situation.

So sklenice can mean:

• a jar
• the jar

depending on context.

In this sentence, English would most naturally translate it as:

• There is a jar of blueberry jam on the table.

because the sentence sounds like it is introducing the jar for the first time.

Not always exactly. This is a vocabulary nuance.

In everyday Czech, borůvky often refers to the small dark berries that English speakers may call bilberries. In many translations, though, blueberries is used because it is the closest familiar English word.

Sometimes cultivated large blueberries are called:

• kanadské borůvky

So for a learner, the safest takeaway is:

• borůvka / borůvky is usually translated as blueberry / blueberries
• but the real-life botanical reference may sometimes be closer to bilberry

For this sentence, blueberry jam is a perfectly natural English rendering.