W domu też podgrzewam mleko w mikrofalówce, kiedy jest zimne.

Polish often leaves out subject pronouns when they are clear from the verb form.

Here, podgrzewam ends in -am, which tells you the subject is I. So:

• podgrzewam = I heat / I warm up

You could add ja for emphasis, but it is not necessary:

• Ja też podgrzewam mleko... = I also heat milk...
  This sounds more contrastive, like I do too.

W domu means at home or in the house/home.

• w = in / at
• domu = the locative form of dom (house/home)

This is used for location, not movement.

Compare:

• w domu = at home
• do domu = to home / homeward / into the house

So in this sentence, w domu tells you where the action happens.

Because dom has an irregular-looking locative singular form: domu.

After w when it means location, Polish usually uses the locative case. For dom, that form is:

• dom → w domu

This is just a form you need to learn as part of the noun’s declension.

Też means also or too.

In this sentence, it suggests something like I also heat milk at home or At home, I also heat milk.

Polish word order is flexible, so też can move around, but its position slightly changes what feels emphasized.

For example:

• W domu też podgrzewam mleko... = At home, I also heat milk...
• Też podgrzewam mleko w domu... = I also heat milk at home...
• Podgrzewam też mleko w domu... = I also heat milk at home...

All are possible, but the original sentence sounds natural.

Podgrzewam comes from podgrzewać, which means to warm up, to heat up, or to reheat a bit.

It is a good choice here because it suggests warming milk that is cold, not necessarily cooking it intensely.

A few useful comparisons:

• grzać = to heat
• podgrzewać = to warm up / heat up
• gotować = to boil / cook

So podgrzewam mleko is very natural for I warm up the milk.

This is about aspect, which is very important in Polish.

• podgrzewać → imperfective
• podgrzać → perfective

Here:

• podgrzewam = I warm up / I am warming up / I habitually warm up
• podgrzeję = I will warm up or I’ll heat it up once

In this sentence, the speaker is talking about a repeated or general habit: whenever the milk is cold, they warm it up. That is why the imperfective verb podgrzewam fits well.

It is the direct object, so yes, it is in the accusative case. But for many neuter inanimate nouns, the accusative looks exactly the same as the nominative.

So:

• nominative: mleko
• accusative: mleko

That is why you do not see a visible change.

Because after w meaning in, Polish uses the locative case for a location.

The dictionary form is:

• mikrofalówka = microwave oven

Its locative singular form is:

• w mikrofalówce = in the microwave

So the pattern is:

• mikrofalówka → w mikrofalówce

This is a very common everyday way to say in the microwave.

Yes. In everyday Polish, mikrofalówka usually means microwave oven.

So:

• w mikrofalówce = in the microwave

If you translated very literally, it might look like it comes from micro-waves, but in normal usage it means the appliance.

It means when it is cold.

Here is the breakdown:

• kiedy = when
• jest = is
• zimne = cold

The subject it is not stated, because Polish often omits pronouns when the meaning is obvious. Here, it refers to mleko.

So the full idea is:

• kiedy mleko jest zimne = when the milk is cold

But Polish can naturally shorten this to:

• kiedy jest zimne

Because zimne agrees with mleko, and mleko is neuter singular.

Adjectives in Polish must agree with the noun they describe.

So:

• zimny = masculine singular
• zimna = feminine singular
• zimne = neuter singular

Since mleko is neuter, you need:

• mleko jest zimne = the milk is cold

Because kiedy jest zimne is a subordinate clause, and Polish normally separates subordinate clauses with commas.

So the comma in:

• W domu też podgrzewam mleko w mikrofalówce, kiedy jest zimne.

is standard Polish punctuation.

In English, punctuation can sometimes be looser in similar sentences, but in Polish this comma is normal.

Yes, sometimes.

A common alternative is gdy:

• ..., gdy jest zimne.

This also means when it is cold.

The difference is small:

• kiedy = very common, neutral
• gdy = also common, sometimes a bit more written or formal

For a learner, kiedy is usually the safest and most straightforward choice.

No, Polish word order is fairly flexible. The sentence you have is natural, but other orders are possible.

For example:

• Też podgrzewam mleko w mikrofalówce w domu, kiedy jest zimne.
• Mleko też podgrzewam w mikrofalówce, kiedy jest zimne.

These can all be grammatical, but the emphasis changes.

The original sentence sounds like a natural neutral statement with mild emphasis on at home too.

Normally, no. The most natural interpretation is that zimne refers to mleko.

Why?

• mleko is the nearest sensible noun
• warming milk because the milk is cold makes logical sense
• dom is masculine, so if it referred to dom, the adjective would need to match that gender differently

So kiedy jest zimne is understood as when the milk is cold.