Learn Hardcore Polish: Ich małżeństwo jest nowe, ale mąż i żona dobrze się znają. - Their marriage is new, but the husband and wife know each other well.

małżeństwo is a neuter singular noun (even though it’s abstract, it grammatically behaves like it).
The adjective nowy (“new”) in neuter singular nominative is nowe.

So:

to małżeństwo – this marriage (neuter)
jest nowe – is new (neuter)

Hence: Ich małżeństwo jest nowe.

What exactly does małżeństwo mean – “marriage” or “married couple”?

Małżeństwo has two main meanings:

The institution / state of being married – marriage
- Ich małżeństwo jest nowe. – Their marriage is new.
A married couple – a (married) couple
- To szczęśliwe małżeństwo. – They are a happy married couple.

Context decides whether you understand it as the abstract “marriage” or as the “couple”. In this sentence, both readings are possible, but learners usually learn it first as “marriage”.

Why is it ale in the middle? Is it the same as English “but”?

Yes. Ale means but and works very similarly to English:

Ich małżeństwo jest nowe, ale mąż i żona dobrze się znają.
Their marriage is new, but the husband and wife know each other well.

Other Polish words like lecz or a can also mean but in some contexts, but:

ale is the most neutral and most common choice here.

What case are małżeństwo, mąż, and żona in?

All three are in the nominative case, because they are subjects of the clauses.

Ich małżeństwo – nominative singular (subject of jest)
mąż i żona – each is nominative singular, together forming a compound plural subject of znają

Breakdown:

małżeństwo – nominative singular neuter
mąż – nominative singular masculine
żona – nominative singular feminine

Why is the verb znają plural?

Because the subject of the second clause is mąż i żona – the husband and (the) wife. That’s two people, so grammatically it’s plural:

(On) zna – he knows
(Ona) zna – she knows
(Oni) znają – they (mixed group / at least one male) know

Here we have a mixed‑gender pair (mąż + żona → oni), so we use znają – third person plural.

Why do we say dobrze się znają and not just dobrze znają?

Znać by itself means to know (someone or something):

Znam Piotra. – I know Piotr.
Znają historię. – They know history.

Znać się is a reflexive form with się that, with people as objects, very often means to know each other:

Oni się dobrze znają. – They know each other well.

So in this sentence:

dobrze się znają = they know each other well

Without się, dobrze znają would need a direct object:

dobrze znają miasto – they know the city well.

What does się do here, exactly?

Się is a reflexive pronoun. With the verb znać się, it creates a reflexive / reciprocal meaning:

znać – to know (someone/something)
znać się – to know oneself / to know each other / to be knowledgeable about something (depending on context)

In this sentence:

mąż i żona dobrze się znają
Literally: the husband and wife well know themselves / each other
Idiomatically: the husband and wife know each other well.

So się is essential here to express the “each other” idea.

Could we put się at the end: dobrze znają się?

Polish clitics like się usually prefer to stand early in the clause, often right after the first stressed element. That’s why:

dobrze się znają sounds completely natural.
dobrze znają się is possible but sounds less neutral and can feel a bit marked or emphatic.

More common natural options:

Mąż i żona dobrze się znają.
Oni się dobrze znają.

In everyday speech and writing, you will almost always hear dobrze się znają rather than dobrze znają się.

Why is it dobrze and not dobrzy here?

Dobrze is an adverb = well.
Dobry / dobra / dobre / dobrzy etc. are adjectives = good.

In this sentence, dobrze modifies the verb znają:

dobrze (how?) znają – they know (how?) well.

So we use the adverb dobrze, not the adjective dobrzy.
(You would use dobrzy to describe people as good in the plural masculine personal form, e.g. dobrzy ludzie – good people.)

What’s the difference between znać, znać się, and wiedzieć?

These often confuse English speakers:

znać – to know (be acquainted with)
- Znam tego człowieka. – I know this person.
- Znam to miasto. – I know this city.
znać się –
- on someone: to know each other
  - Oni się znają. – They know each other.
- on something: to be knowledgeable / an expert in
  - On się zna na komputerach. – He knows about computers / is good with computers.
wiedzieć – to know (a fact)
- Wiem, że oni są małżeństwem. – I know that they are married.
- Wiesz, gdzie mieszkają? – Do you know where they live?

In our sentence, we talk about two people knowing each other, so we must use znać się:
dobrze się znają.

Could we say Ich małżeństwo jest młode instead of nowe? What’s the nuance?

Both nowe and młode can be used about a marriage, but they feel slightly different:

nowe – new
Focus on the short time since it started.
Ich małżeństwo jest nowe. – Their marriage is new / recent.
młode – literally young
More idiomatic about young people or a young couple, but can also describe a marriage in stylistic or poetic language:
- To młode małżeństwo. – This is a young married couple.
- Ich małżeństwo jest jeszcze młode. – Their marriage is still young.

In everyday neutral speech, jest nowe is clearer for “is new”, while młode małżeństwo is very common as a fixed phrase meaning a young married couple.

How do you pronounce małżeństwo, and what do the letters with accents mean?

Małżeństwo is pronounced roughly like: [mau-ŻEN-stvo].

Key points:

ł – like English w in we: mał ≈ maw
rz – usually pronounced like ż, similar to zh in vision
ę – nasal vowel; before n/ń it sounds like “en”, here it’s close to “en”: -żeń- ≈ zhen
ń – soft n, like ny in canyon
w – like English v

So:

mał-żen-stwo → mau-zhens-tvo (approximate English-friendly version)

The spelling shows historical sounds and nasal vowels, but for understanding and being understood, approximating it as “mau-zhens-tvo” is good enough at first.