Gdy dzieci jedzą kanapki, mama pije kawę i czyta wiadomości.

Here gdy means when or while.

In this sentence, Gdy dzieci jedzą kanapki, mama pije kawę i czyta wiadomości, it introduces a time clause:

• Gdy dzieci jedzą kanapki = When/While the children are eating sandwiches

Gdy and kiedy can often both mean when, and in many everyday contexts they are interchangeable. However:

• gdy can sound a little more written or narrative
• kiedy is often more common in everyday speech

So you could also say:

• Kiedy dzieci jedzą kanapki, mama pije kawę i czyta wiadomości.

Polish normally uses a comma to separate a subordinate clause from the main clause.

Here:

• Gdy dzieci jedzą kanapki = subordinate clause
• mama pije kawę i czyta wiadomości = main clause

So the comma is required:

• Gdy dzieci jedzą kanapki, mama pije kawę i czyta wiadomości.

This is similar to English sentences like:

• When the children eat sandwiches, Mom drinks coffee and reads the news.

Dzieci is the plural form of dziecko (child).

So:

• dziecko = child
• dzieci = children

This is an irregular noun, so the plural is not formed in a simple predictable way.

In the sentence:

• dzieci jedzą = the children eat / are eating

You would use:

• dziecko je = the child eats / is eating
• dzieci jedzą = the children eat / are eating

Jedzą is the correct 3rd person plural present tense of jeść (to eat).

Conjugation of jeść in the present tense:

• jem = I eat
• jesz = you eat
• je = he/she/it eats
• jemy = we eat
• jecie = you all eat
• jedzą = they eat

Because dzieci is plural, the verb must also be plural:

• dzieci jedzą = children eat

This verb is somewhat irregular, so its forms need to be learned rather than built mechanically.

Kanapki is the accusative plural of kanapka (sandwich).

After the verb jeść (to eat), the thing being eaten is usually in the accusative case.

So:

• kanapka = sandwich
• kanapki = sandwiches

In this noun’s pattern, the accusative plural looks the same as the nominative plural, so kanapki can mean:

• sandwiches as the subject in some sentences
• sandwiches as the object here

In this sentence it is the object:

• dzieci jedzą kanapki = the children are eating sandwiches

Because kawa is the direct object of pije (drinks), it must be in the accusative case.

So:

• kawa = coffee (nominative, dictionary form)
• kawę = coffee (accusative singular)

Compare:

• Kawa jest gorąca. = The coffee is hot.
  Here kawa is the subject.
• Mama pije kawę. = Mom is drinking coffee.
  Here kawę is the object.

This is a very common pattern in Polish with feminine nouns ending in -a:

• nominative singular: -a
• accusative singular: -ę

Wiadomości is the plural form of wiadomość (message, piece of news, news item), and here it is in the accusative plural.

For this noun, the accusative plural looks the same as the nominative plural:

• wiadomości = nominative plural
• wiadomości = accusative plural

So even though it is the object of czyta (reads), the form does not change visibly.

This is very common in Polish, especially with many non-masculine nouns.

Depending on context, czyta wiadomości can mean:

• reads the news
• reads messages

Because there is only one subject: mama.

She is doing two actions, but the subject is still singular, so both verbs stay in 3rd person singular:

• mama pije = Mom drinks
• mama czyta = Mom reads

Polish often uses one subject with multiple coordinated verbs:

• Mama pije kawę i czyta wiadomości.
• Tata siedzi i ogląda telewizję.

If the subject were plural, the verbs would be plural:

• Rodzice piją kawę i czytają wiadomości. = The parents drink coffee and read the news.

Not exactly. Polish present tense often covers both:

• simple present: eat, drinks, reads
• present continuous: are eating, is drinking, is reading

So this sentence could mean:

• When the children eat sandwiches, Mom drinks coffee and reads the news. or
• While the children are eating sandwiches, Mom is drinking coffee and reading the news.

The exact meaning depends on context.

Because the verbs here are imperfective:

• jedzą
• pije
• czyta

they are natural for ongoing, repeated, or habitual actions.

Yes. Polish word order is more flexible than English, because case endings show grammatical roles.

This sentence is neutral and natural:

• Gdy dzieci jedzą kanapki, mama pije kawę i czyta wiadomości.

But you could also say:

• Mama pije kawę i czyta wiadomości, gdy dzieci jedzą kanapki.

That means essentially the same thing.

You can also move words for emphasis, but some versions sound more natural than others. For learners, the original sentence is a very good standard pattern:

• time clause first
• main clause second

Mama is completely normal and very common in Polish.

It can mean:

• Mom
• mum/mom
• sometimes simply the mother in a family context

It is not too childish in ordinary speech. In fact, it is usually more natural than matka in everyday family situations.

Compare:

• Mama pije kawę. = natural, everyday
• Matka pije kawę. = more formal, colder, or more descriptive

So in this sentence, mama is exactly what you would expect.

I means and.

Here it connects the two actions done by mama:

• pije kawę i czyta wiadomości = drinks coffee and reads the news

Polish does not need to repeat i before each element unless you want a special rhythm or emphasis.

So this is normal:

• mama pije kawę i czyta wiadomości

If you had a longer list, you might repeat i for emphasis, but that is optional and stylistic:

• Mama pije kawę, i czyta wiadomości, i rozmawia przez telefon. This has a more expressive feel, not the neutral one.

A few pronunciation points that often trouble English speakers:

• gdy
  The g is a normal hard g.
  The dy is softer than English dee, but not exactly the same as English sounds.
  It is roughly like gdi with a softened d sound.

• jedzą
  The final ą is a nasal vowel. In normal speech, before the end of a word, it often sounds somewhat like on/om, depending on context.
  So jedzą is roughly YE-dzom, but not exactly.

• kawę
  The final ę is another nasal vowel. At the end of a word, many speakers pronounce it less strongly nasally in casual speech.
  Roughly, KAH-veh with a nasal ending, though the exact sound is hard to match in English.

Also:

• dz in jedzą is one sound cluster, like the ds part of beds, but voiced.

It can describe either, depending on context.

Because the verbs are in the present tense and are imperfective, the sentence can mean:

• a general routine: Whenever/When the children eat sandwiches, Mom drinks coffee and reads the news
• something happening right now: While the children are eating sandwiches, Mom is drinking coffee and reading the news

Polish often leaves this distinction to context rather than changing the verb form the way English often does.

So the sentence is naturally a bit broader than a single fixed English translation.