Špíz leží uprostřed roštu.

Because uprostřed normally takes the genitive case in Czech.

• base form: rošt
• genitive singular: roštu

So uprostřed roštu means in the middle of the grate / grill rack.

This is similar to other Czech expressions that require the genitive after a preposition or adverb-like word.

Špíz is in the nominative singular because it is the subject of the sentence — the thing that is lying somewhere.

So the structure is:

• Špíz = subject
• leží = verb
• uprostřed roštu = location

Czech often prefers a more specific verb for position or location.

• leží = lies, is lying, or more generally is located
• je = is

In English, you might say The skewer is in the middle of the grate, but Czech naturally says The skewer lies / is lying in the middle of the grate.

This is very common with objects or places:

• Kniha leží na stole. = The book is lying on the table.
• Město leží u řeky. = The city lies by the river.

So leží does not always mean literal lying in a dramatic sense; it often just expresses position.

Leží is the 3rd person singular present tense of ležet.

That means it matches a singular subject such as špíz.

A simple breakdown:

• infinitive: ležet = to lie
• já ležím = I lie / am lying
• ty ležíš = you lie / are lying
• on/ona/ono leží = he/she/it lies / is lying

Here špíz is grammatically singular, so Czech uses leží.

A rough English-friendly guide:

• Špíz ≈ shpeez
• leží ≈ leh-zhee
• uprostřed ≈ oo-pros-tryed or oo-pros-chtred depending on how closely you imitate Czech sounds
• roštu ≈ rosh-too

A few useful sound notes:

• š sounds like sh
• ž sounds like the s in measure
• í is a long ee
• ř is a special Czech sound with no exact English equivalent; learners usually need time with it

Yes, uprostřed is written as one word.

It means:

• in the middle of
• amid
• centrally within

In this sentence, uprostřed roštu means in the middle of the grate.

You may also see related expressions such as:

• ve středu = in the center
• v prostředku = in the middle, inside the middle part
• uprostřed = in the middle of

They can overlap, but uprostřed + genitive is a very standard pattern.

Czech has no articles like English a/an/the.

So:

• Špíz can mean a skewer or the skewer
• roštu can mean of a grate or of the grate

The exact meaning depends on context.

English requires an article, but Czech usually leaves that information unstated unless something else makes it clear.

Yes, Czech word order is relatively flexible because the grammar is shown partly through case endings.

The neutral order here is:

• Špíz leží uprostřed roštu.

But you could also say, for example:

• Uprostřed roštu leží špíz.

That version puts more focus on the location first: In the middle of the grate lies the skewer.

So the meaning stays basically the same, but the emphasis changes.

Yes, špíz is a masculine inanimate noun.

That matters because Czech nouns belong to genders, and gender affects:

• adjective endings
• pronouns
• some verb-related agreement patterns
• case endings

Here you do not see much change on špíz itself, because it is in the nominative singular, but knowing its gender is still useful for building other sentences.

It can depend on context.

In everyday usage, špíz often refers to a kebab/skewer dish — pieces of food on a skewer. In some contexts, it may also refer to the skewer arrangement as a whole rather than just the bare stick.

So in a sentence like this, the exact image depends on the situation:

• the skewer as an object on the grill
• the grilled kebab/skewer lying there

Czech often leaves that slightly broad unless context narrows it down.

Not as a full replacement, because they mean different things.

• na roštu = on the grate
• uprostřed roštu = in the middle of the grate

If you say:

• Špíz leží na roštu.

that tells us where it is generally.
If you say:

• Špíz leží uprostřed roštu.

that gives a more precise location.

You can even combine both ideas in a longer sentence if needed, but in this sentence uprostřed roštu already gives the specific position.