Převodovka je nová.

• převodovka = gearbox or transmission
• je = is
• nová = new

So the sentence is literally Gearbox is new, which in natural English is The gearbox is new or The transmission is new.

Because nová has to agree with převodovka in gender, number, and case.

Here:

• převodovka is feminine
• it is singular
• it is in the nominative case

So the adjective nový changes to its feminine singular nominative form:

• masculine: nový
• feminine: nová
• neuter: nové

That is why you get Převodovka je nová.

In this sentence, you can tell partly from the noun ending and partly from the adjective agreement.

Many Czech nouns ending in -a are feminine, and převodovka is one of them. Because it is feminine, the adjective must also use the feminine form: nová.

So the sentence itself gives you a clue:

• převodovka → feminine noun
• nová → feminine adjective form

Je is the 3rd person singular form of být (to be), so it means is.

• já jsem = I am
• ty jsi = you are
• on/ona/ono je = he/she/it is

In Převodovka je nová, the noun is singular, so Czech uses je.

Normally, no. In a regular sentence like this, you should say Převodovka je nová.

Leaving out je might happen in:

• headlines
• notes
• very compressed or poetic style

But for standard spoken and written Czech, keep je.

Czech does not have articles like English a/an and the.

So Převodovka je nová can mean:

• A gearbox is new
• The gearbox is new

Which one is meant depends on context.

This is very normal in Czech, and learners have to get used to understanding definiteness from the situation rather than from an article.

It is in the nominative case.

That is because převodovka is the subject of the sentence: it is the thing that is new.

The adjective nová is also in nominative because it is a predicate adjective agreeing with the subject.

So:

• převodovka = nominative singular feminine
• nová = nominative singular feminine

It is an adjective.

More specifically, it is the feminine singular nominative form of the adjective nový (new).

In this sentence, it comes after je and describes the subject, so it works like a predicate adjective:

• Auto je nové. = The car is new.
• Převodovka je nová. = The gearbox is new.

A rough pronunciation guide:

• Převodovka ≈ przheh-VOH-tov-ka
• je ≈ yeh
• nová ≈ NOH-vaa

A few important points:

• ř is a famous Czech sound. It is difficult for English speakers. It is something like a rolled or raised r combined with a zh-like sound.
• j in Czech is pronounced like English y in yes.
• á is a long vowel, so nová has a long final a.

You do not need perfect ř right away. Being understandable matters first.

In Czech, the stress is usually on the first syllable of each word.

So:

• PŘEvodovka
• JE
• NOvá

That means Převodovka je nová is stressed roughly like this:

• PŘE-vo-dov-ka je NO-vá

Even when a vowel is long, like á in nová, the stress still stays on the first syllable.

Yes, Czech word order is fairly flexible, although the neutral order here is:

Převodovka je nová.

You may also hear:

• Nová je převodovka.
• Je nová převodovka. (less neutral, depends on context)

Different word orders can change emphasis or information focus, not the basic meaning.

For a beginner, the safest default is:

• subject + je + adjective

So Převodovka je nová is the best standard form to learn first.

You replace je with není:

Převodovka není nová.

That means The gearbox is not new.

This is the normal way to negate sentences with být (to be) in the present tense.

The basic adjective is nový (new), but it changes to match the noun.

Examples in nominative singular:

• masculine: motor je nový = the engine is new
• feminine: převodovka je nová = the gearbox is new
• neuter: auto je nové = the car is new

This is one of the most important patterns in Czech grammar: adjectives must agree with the noun they describe.