V koupelně máme novou pračku a dnes v ní peru prádlo, ponožky i košile.

Because the preposition v meaning in normally requires the locative case when it expresses location.

• basic form: koupelna = bathroom
• after v for location: v koupelně = in the bathroom

So -a changes to -ě because the noun is feminine and is being used in the locative.

Because pračku is the direct object of máme.

The verb mít (to have) takes the accusative case:

• nová pračka = a new washing machine (dictionary / nominative form)
• máme novou pračku = we have a new washing machine

Both the adjective and the noun change:

• nová → novou
• pračka → pračku

This is a very common Czech pattern with feminine singular nouns in the accusative.

Pračka means washing machine.

It comes from the verb prát = to wash laundry / to wash clothes.

So:

• prát = to wash clothes
• pračka = a machine used for washing clothes

Czech often forms nouns this way from verbs.

Ní refers back to pračka.

So:

• pračka = washing machine
• v ní = in it

Since pračka is a feminine noun, the pronoun must match it:

• v něm would be for a masculine or neuter noun in some contexts
• v ní is the correct form for a feminine noun here

Also, after v, the pronoun is in the locative case, just like v koupelně.

Peru is the 1st person singular present tense of prát.

So:

• prát = to wash laundry / clothes
• peru = I wash / I am washing

This verb changes its stem, so it is not formed in a completely predictable way from the infinitive:

• prát
• já peru

That is why learners usually need to memorize it.

It can mean both.

In Czech, the present tense often covers both:

• I wash
• I am washing

The exact meaning depends on context. Here, because of dnes (today) and the overall situation, it is naturally understood as something like I’m washing laundry in it today.

Because prádlo is usually a mass noun in Czech, similar to laundry in English.

So:

• prádlo = laundry / washing / clothes to be washed

It is grammatically singular, even though it refers to many items. That is why the sentence uses prádlo, not a plural like prádla.

They are also direct objects of peru, so they are in the accusative.

However, for these particular feminine plural nouns, the accusative plural looks the same as the nominative plural:

• ponožky = socks
• košile = shirts

So even though they are objects, their forms do not visibly change here.

That can be confusing at first: the case is different in function, but the spelling happens to stay the same.

Here i means something like and also, as well as, or sometimes even depending on context.

So:

• ponožky a košile = socks and shirts
• ponožky i košile = socks and also shirts

In this sentence, i slightly emphasizes that shirts are included too.

It is not very dramatic here; it just adds a small sense of also.

Yes, Czech word order is fairly flexible.

This sentence has:

• V koupelně máme novou pračku = In the bathroom we have a new washing machine
• a dnes v ní peru... = and today I wash in it...

Placing dnes early gives it mild emphasis. But other word orders are possible, for example:

• A v ní dnes peru...
• A peru v ní dnes...

These may sound slightly different in emphasis or flow, but the basic meaning stays the same.

Czech word order is often guided by:

• what is already known
• what is new or emphasized
• what sounds natural in context

Because the sentence has two different subjects in effect:

• máme = we have
• peru = I wash

So the speaker is saying:

• we have a new washing machine in the bathroom
• I am using it today to wash laundry, socks, and shirts

This kind of subject shift is completely normal in Czech, just as in English.

Yes. Starting with V koupelně puts the location first.

That makes the sentence feel natural if the speaker wants to set the scene first:

• In the bathroom, we have a new washing machine...

Czech often puts time or place expressions at the beginning when they provide the background for the rest of the sentence.

So this word order is not random; it helps organize the information naturally.