Chci postavit nový dům.

• chci = I want
• postavit = to build / to put up / to erect
• nový = new
• dům = house

So the structure is literally:

• chci
  • postavit = I want to build
• nový dům = a new house

Czech often works very neatly here: want + infinitive + object.

Chtít is the dictionary form, meaning to want.

In the sentence, you need the 1st person singular present form, because the speaker is I.
So:

• chtít = to want
• chci = I want

A few present-tense forms of chtít are:

• chci = I want
• chceš = you want
• chce = he/she/it wants
• chceme = we want
• chcete = you want / you all want
• chtějí = they want

So Chci postavit nový dům means I want to build a new house.

After chci (I want), Czech normally uses an infinitive, just like English uses to build after want.

Compare:

• Chci spát. = I want to sleep.
• Chci jíst. = I want to eat.
• Chci postavit nový dům. = I want to build a new house.

So postavit is in the infinitive because it is the second verb, dependent on chci.

This is a very common Czech question, because it involves aspect.

• stavět = imperfective: focuses on the process, repeated activity, or general action of building
• postavit = perfective: focuses on completing the building, getting it done

In this sentence, postavit suggests I want to build/finish a new house, with the idea of reaching a completed result.

Very roughly:

• Chci stavět nový dům. = I want to be building / I want to work on building a new house.
• Chci postavit nový dům. = I want to build a new house, with completion implied.

English does not mark this contrast as clearly, so learners often need time to get used to it.

Because nový has to agree with dům in:

• gender
• number
• case

Here, dům is:

• masculine inanimate
• singular
• accusative (because it is the direct object of postavit)

For masculine inanimate nouns, the accusative singular looks the same as the nominative singular, so you get:

• nový dům

That is why both words look like their basic dictionary-like form here.

Because Czech case endings do not always visibly change every noun.

Here, dům is indeed the direct object, so it is in the accusative. But for a masculine inanimate singular noun like dům, the accusative is the same as the nominative:

• nominative: dům
• accusative: dům

So the case is shown by grammar and function, even though the form does not change.

The adjective also matches that pattern:

• nominative: nový dům
• accusative: nový dům

No visible change, but the case is still accusative.

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

So:

• nový dům can mean a new house
• or the new house

Which one is meant depends on context.

In this sentence, English usually translates it as a new house, but Czech itself does not need a separate word for a.

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

The neutral order here is:

• Chci postavit nový dům.

But other orders are possible for emphasis, for example:

• Nový dům chci postavit. = It is a new house that I want to build.
• Postavit nový dům chci. = Building a new house is what I want to do.

These alternatives are not random; they usually change the focus or emphasis. For a basic textbook sentence, Chci postavit nový dům is the most natural neutral order.

Because Czech often leaves out subject pronouns when they are already clear from the verb form.

• chci already means I want
• so já is usually unnecessary

You could say:

• Já chci postavit nový dům.

But that would usually add emphasis, something like:

• I want to build a new house.
• I want to build a new house, not someone else.

So the version without já is the normal unmarked one.

A simple learner-friendly approximation is:

kh-tsee POS-ta-vit NO-vee doom

A few helpful points:

• ch in Czech is not like English ch in chair. It is a rough sound, like the ch in German Bach or Scottish loch.
• c is pronounced ts, so chci sounds roughly like kh-tsee.
• ý is a long vowel, so nový has a long final ee sound.
• ů in dům is pronounced like a long oo.

So:

• chci ≈ kh-tsee
• postavit ≈ POS-ta-vit
• nový ≈ NO-vee
• dům ≈ doom

Not always. Its core meaning is something like to put up / erect / build, and the best English translation depends on context.

With dům, to build is the natural choice:

• postavit dům = to build a house

But in other contexts, postavit can also mean things like:

• postavit most = build a bridge
• postavit stan = put up a tent
• postavit něco na stůl = put something on the table

So here, build is exactly right, but the verb itself is a bit broader than just construction.

You keep postavit nový dům and change chci:

• Chceš postavit nový dům. = You want to build a new house.
• Chce postavit nový dům. = He/she wants to build a new house.
• Chceme postavit nový dům. = We want to build a new house.
• Chcete postavit nový dům. = You want / You all want to build a new house.
• Chtějí postavit nový dům. = They want to build a new house.

This is a useful pattern to memorize:

[form of chtít] + infinitive + object