Learn Hardcore Polish: W naszej rodzinie jest tradycja, że w niedzielę jemy razem śniadanie. - In our family there is a tradition that on Sundays we eat breakfast together.

The preposition w (in) + a static location normally takes the locative case.
The noun rodzina (family) is feminine singular. Its locative form is rodzinie.
The pronoun nasza (our) must agree with rodzinie in gender, number and case:
- nominative: nasza rodzina (our family – subject)
- locative: w naszej rodzinie (in our family)

So:

nasza rodzina – nominative (who? what?)
w naszej rodzinie – locative after w (where? in what?)

What case is rodzinie in, and how do I recognize it?

Rodzinie is in the locative singular.

How to recognize it here:

It follows w (in), and we are talking about a place/state, not movement.
For many feminine nouns ending in -a, the locative singular often ends in -ie:
- rodzina → w rodzinie
- szkoła → w szkole
- kawa → w kawie

Locative is used mainly:

after some prepositions (especially w, na, o, po, przy in certain meanings),
and almost nowhere else, so the preposition + ending combination is the usual clue.

Why is it jest tradycja and not mamy tradycję? Are both correct?

Both are possible, but they sound slightly different.

W naszej rodzinie jest tradycja, że…
Literally: In our family there is a tradition that…
This sounds a bit more neutral or formal, simply stating that such a tradition exists.
W naszej rodzinie mamy tradycję, że…
Literally: In our family we have a tradition that…
This puts more emphasis on we have / keep this tradition; it can feel a bit more personal.

Grammatically:

jest tradycja – jest (there is) + tradycja in the nominative.
mamy tradycję – mamy (we have) + tradycję in the accusative (object of mieć).

In everyday speech, many people might actually prefer Mamy tradycję, że w niedzielę… because it sounds very natural and conversational.

Why is there a comma before że?

In Polish, you must put a comma before że when it introduces a subordinate clause.

The structure is:

Main clause: W naszej rodzinie jest tradycja,
Subordinate clause (what tradition?): że w niedzielę jemy razem śniadanie.

Rule of thumb:

If że means that (introducing a clause), put a comma before it:
- Myślę, że to dobry pomysł.
- On powiedział, że nie przyjdzie.
- Jest tradycja, że…

So the comma is not optional here; it’s required by standard Polish punctuation.

What does że do in this sentence? Could I leave it out?

Że works like English that introducing a content clause:

jest tradycja, że …
→ there is a tradition that …

It links the noun tradycja with a whole clause explaining its content.

Can you omit it here? No, not in this structure.
You cannot say:

✗ W naszej rodzinie jest tradycja, w niedzielę jemy razem śniadanie. (incorrect as a single sentence)

If you want to avoid że, you must change the structure, for example:

W naszej rodzinie mamy tradycję: w niedzielę jemy razem śniadanie.
(Here the colon replaces że, and the second part is more like an explanation or example.)

Why is it w niedzielę and not w niedzieli or something else?

W niedzielę uses the accusative case to express time when something happens.

Patterns with days of the week:

w poniedziałek, we wtorek, w środę, w czwartek, w piątek, w sobotę, w niedzielę

This is a common Polish pattern: w + accusative = on [day], often with a habitual meaning:

W poniedziałek pracuję z domu. – I work from home on Monday / on Mondays.
W niedzielę jemy razem śniadanie. – We eat breakfast together on Sunday / on Sundays.

W niedzieli would be locative (e.g. Myślę o niedzieli – I’m thinking about Sunday), but after w for time we don’t use locative, we use accusative.

Does w niedzielę mean “on Sunday” (one time) or “on Sundays” (every Sunday)?

By itself, w niedzielę can mean either:

one specific Sunday, or
a repeated, habitual action (on Sundays in general).

Context usually tells you which is meant. In this sentence:

W naszej rodzinie jest tradycja, że w niedzielę jemy razem śniadanie.

Because it talks about a tradition, it clearly means every Sunday / on Sundays.

You can also say:

W niedziele jemy razem śniadanie. (plural niedziele)
This makes the “every Sunday” reading even more explicit, but in practice both versions can describe a weekly habit, and the version in the sentence is very natural.

Why is the word order jemy razem śniadanie? Could I say razem jemy śniadanie or jemy śniadanie razem?

All of these are grammatically correct; they differ only in emphasis and rhythm:

jemy razem śniadanie – neutral, very natural:
- subject implied (we), verb (jemy), adverb (razem), object (śniadanie).
razem jemy śniadanie – emphasizes together at the start:
- like English Together we eat breakfast.
jemy śniadanie razem – also fine; razem at the end can carry a bit of stress, similar to We eat breakfast together.

Polish word order is fairly flexible; the main thing is that function (who does what to whom) is shown by endings, not by word order. Here, śniadanie is in the neuter singular accusative, so it is clearly the object whichever position it has.

Why is śniadanie used without anything like “a” or “the”?

Polish does not have articles (no equivalents of a, an, the). So nouns normally appear without any article:

śniadanie – breakfast
rodzina – (a/the) family
tradycja – (a/the) tradition

Context decides whether you would translate it as a or the in English:

Jemy śniadanie. – We are eating (the / our) breakfast.
Kupiłem samochód. – I bought a car.

So jemy razem śniadanie simply means we eat breakfast together, and English adds the article according to its own rules, but Polish doesn’t show that distinction.

Why is the verb jemy used here, and not something like jadamy?

Both can be used, but jemy is the standard, neutral choice.

jemy – present tense of jeść (to eat), 1st person plural:
- jemy can mean:
  - we are eating (now), or
  - we eat (habitually). In this sentence, the habitual meaning is clear from the word tradycja.
jadamy – present tense of jadać, a habitual/frequentative verb:
- emphasizes that something happens regularly or as a custom:
  - W niedzielę jadamy razem śniadanie. This fits well with the idea of tradition, but sounds a bit more stylized or bookish. In everyday speech, most people would still say jemy.

So jemy is perfectly correct and natural for describing traditions and routines.

What are the genders of rodzina and tradycja, and how does that affect the sentence?

Both rodzina and tradycja are feminine singular nouns, which affects the form of adjectives and pronouns.

rodzina (family) – feminine singular
- nominative: nasza rodzina (our family)
- locative: w naszej rodzinie
tradycja (tradition) – feminine singular
- nominative: ta tradycja (this tradition)
- accusative: tradycję (if it were an object, e.g. mamy tradycję)

Because rodzina is feminine, nasza must also take the feminine form:

nasza rodzina (f.)
not nasz rodzina (m.) or nasze rodzina (n.)

Similarly with tradycja:

ta tradycja (this tradition – feminine)
not ten tradycja or to tradycja.

In the sentence we see this with naszej in w naszej rodzinie (feminine, locative, singular).