Mam jedno rodzeństwo: siostrę.

I have one sibling: a sister.

Breakdown of Mam jedno rodzeństwo: siostrę.

• ja: I
• mieć: to have
• jeden: one
• siostra: the sister
• rodzeństwo: the sibling

Questions & Answers about Mam jedno rodzeństwo: siostrę.

Is rodzeństwo singular or plural? It looks like a plural word but means sibling(s).

Rodzeństwo is a collective noun in Polish:

• Grammatically: singular, neuter
• Meaning: siblings as a group, or brother(s) and/or sister(s)

So:

• Mam rodzeństwo. = I have siblings. / I have a sibling/siblings.
• You treat rodzeństwo like one neuter noun in grammar, even though in meaning it refers to several people (or possibly just one).

Why is it jedno rodzeństwo and not jeden rodzeństwo?

The form of “one” has to agree in gender with the noun:

• masculine: jeden (e.g. jeden brat – one brother)
• feminine: jedna (e.g. jedna siostra – one sister)
• neuter: jedno (e.g. jedno dziecko – one child, jedno rodzeństwo)

Since rodzeństwo is neuter, you must use jedno, not jeden or jedna.

So:

• Mam jedno rodzeństwo. – I have one sibling (one set of siblings):
• Mam jedną siostrę. – I have one sister.

Is Mam jedno rodzeństwo: siostrę. a natural way to say this, or would Poles say it differently?

It’s understandable and grammatically correct, but in everyday speech, Poles would more commonly say:

• Mam jedną siostrę. – I have one sister.
• or simply Mam siostrę. – I have a sister.

Using rodzeństwo with jedno is less common because rodzeństwo usually implies the idea of having siblings in general, and speakers often switch straight to the concrete person:

• Mam rodzeństwo: starszą siostrę. – I have siblings: an older sister.

Your sentence with the colon is fine as a written, slightly more formal way of specifying what that rodzeństwo is.

Why is it siostrę and not siostra?

Because of case.

The verb mieć (mam = I have) takes a direct object in the accusative case.

• Nominative (dictionary form): siostra (used for the subject)
  • Moja siostra jest w domu. – My sister is at home.
• Accusative (direct object after mam): siostrę
  • Mam siostrę. – I have a sister.

In your sentence, siostrę is the object of mam, so it must be in the accusative.

Why is there a colon (:) in Mam jedno rodzeństwo: siostrę.? Is that normal in Polish?

Yes, that colon is used very similarly to English. It introduces an explanation or specification of what came before.

• Mam jedno rodzeństwo: siostrę.
  Literally: I have one sibling: a sister.
  The part after the colon specifies what that rodzeństwo is.

In speech, you would just pause slightly, like in English. You could also write:

• Mam jedno rodzeństwo – siostrę.
• Mam jedno rodzeństwo, siostrę.

All three are possible in writing; with a comma it looks more like an apposition, with a dash or colon it feels a bit more “explaining” or emphatic.

What is the difference between saying Mam jedno rodzeństwo: siostrę. and Mam jedną siostrę.?

The meaning is basically the same (you have exactly one sister), but there is a nuance:

• Mam jedną siostrę.
  – Direct, simple, everyday way to say I have one sister.
• Mam jedno rodzeństwo: siostrę.
  – Literally I have one sibling: a sister.
  – Sounds a bit more formal/bookish or like you’re answering a survey question about rodzeństwo (siblings) and then clarifying.

In normal conversation, Mam jedną siostrę or simply Mam siostrę would be much more common.

When should I use rodzeństwo instead of brat or siostra?

Use rodzeństwo when you are talking about your siblings as a group, or when you don’t want to say exactly who they are:

• Masz rodzeństwo? – Do you have any siblings?
• Tak, mam rodzeństwo. – Yes, I have siblings.
• Nie mam rodzeństwa. – I have no siblings.

Use brat / siostra when you want to be specific:

• Mam jednego brata i dwie siostry. – I have one brother and two sisters.
• Mam siostrę. – I have a sister.

Your sentence combines both:

• rodzeństwo (general: I have siblings)
• siostrę (specific: that sibling is a sister)

How would I say I have no siblings and I have two siblings: a brother and a sister in Polish?

These examples are closely related to the grammar in your sentence:

1. I have no siblings.
   → Nie mam rodzeństwa.

   • nie mam requires the genitive case, so rodzeństwo becomes rodzeństwa.

2. I have two siblings: a brother and a sister.
   → Mam dwoje rodzeństwa: brata i siostrę.

   • With mixed‑gender children/siblings, Polish often uses collective numerals:
     • dwoje rodzeństwa – two siblings
     • troje rodzeństwa – three siblings
   • brata and siostrę are both in the accusative, as they are objects of mam.

These follow the same patterns as in your original sentence: mam + accusative object, and rodzeństwo used for the general idea of siblings.