Muszę zapamiętać ten adres.

In Polish, musieć (to have to / must) is followed directly by an infinitive.

So the pattern is:

• muszę zrobić = I have to do
• muszę iść = I have to go
• muszę zapamiętać = I have to memorize / remember

Unlike English, Polish does not use a separate word like to before the infinitive here.

So:

• Muszę zapamiętać ten adres. is correct.
• Muszę to zapamiętać ten adres. would be wrong unless to meant it, and even then the sentence structure would need to be different.

Muszę is the 1st person singular present form of musieć (to have to / must).

It means I have to or I must.

A few related forms:

• muszę = I have to
• musisz = you have to
• musi = he/she/it has to
• musimy = we have to
• musicie = you all have to
• muszą = they have to

So in this sentence, muszę tells you the subject is I, even though Polish often omits the pronoun ja.

Polish usually leaves out subject pronouns when they are already clear from the verb ending.

Since muszę already means I have to, adding ja is often unnecessary:

• Muszę zapamiętać ten adres. = normal, natural
• Ja muszę zapamiętać ten adres. = also correct, but more emphatic

You would add ja if you want contrast or emphasis, for example:

• Ja muszę zapamiętać ten adres, nie ty. = I have to remember this address, not you.

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

• pamiętać is imperfective
• zapamiętać is perfective

The perfective verb zapamiętać means something like:

• to memorize
• to commit to memory
• to manage to remember after learning it

It focuses on the result: getting the address into your memory.

By contrast, pamiętać usually means to remember / to have in mind, describing a state rather than the completed act of memorizing.

Compare:

• Muszę zapamiętać ten adres. = I need to learn it so I will remember it.

• Muszę pamiętać o spotkaniu. = I have to remember the meeting / keep it in mind.

So in your sentence, zapamiętać is used because the speaker needs to store the address in memory.

Yes, the direct object usually goes into the accusative in Polish. But in this sentence, ten adres looks the same in the nominative and accusative.

Here is why:

• adres is masculine inanimate
• For masculine inanimate nouns, the accusative singular is usually the same as the nominative singular
• The demonstrative adjective matches that pattern

So:

• nominative: ten adres
• accusative: ten adres

That is why the sentence uses ten adres, even though it is the object.

Adres is in the accusative singular, because it is the direct object of zapamiętać.

However, as a masculine inanimate noun, its accusative form is identical to the nominative:

• nominative: ten adres
• accusative: ten adres

This can be confusing for English speakers, because the form does not visibly change, but grammatically it is still accusative.

You usually learn the grammatical gender of nouns along with the noun itself.

Adres is masculine inanimate. That matters because gender affects:

• adjective forms
• pronouns
• past tense forms
• case endings
• accusative behavior

For masculine nouns in the singular:

• masculine animate often has accusative = genitive
• masculine inanimate usually has accusative = nominative

So compare:

• Widzę tego psa. (dog, masculine animate)
• Widzę ten adres. (address, masculine inanimate)

That difference is why you get ten adres, not tego adresu.

A rough pronunciation is:

za-pa-MYEN-tyach
—but that is only approximate.

A few important points:

• ć is a soft sound, somewhat like a very soft ch / ty sound
• ę is a nasal vowel, though in normal speech its pronunciation changes depending on position
• In zapamiętać, the ę before t is often pronounced approximately like en or em in natural speech
• Stress in Polish is usually on the second-to-last syllable, so here the stress falls on mię: za-pa-MIĘ-tać

A learner-friendly approximation:

• zah-pah-MYEN-tach

Not perfect, but useful as a start.

Only ten adres works in this sentence.

Why?

Because zapamiętać takes a direct object, and direct objects usually go in the accusative.

For adres:

• nominative: adres
• accusative: adres
• genitive: adresu

And for the demonstrative:

• nominative/accusative masculine inanimate: ten
• genitive: tego

So:

• Muszę zapamiętać ten adres. = correct
• Muszę zapamiętać tego adresu. = incorrect here
• Muszę zapamiętać ten adresu. = incorrect

You would use adresu in other grammatical contexts, for example:

• Nie znam adresu. = I don't know the address.

Yes. Polish word order is more flexible than English, although not completely free.

The most neutral order here is:

• Muszę zapamiętać ten adres.

But you could also say:

• Ten adres muszę zapamiętać. This puts more emphasis on this address.

• Zapamiętać muszę ten adres. This is more marked and sounds more literary, emotional, or contrastive.

So the original sentence is the most standard and neutral version.

It is not always completely impossible, but it is much less natural in this context.

If you want to say I need to memorize this address, then:

• Muszę zapamiętać ten adres. is the natural choice.

Muszę pamiętać ten adres sounds more like I have to keep remembering this address, which is not usually what speakers mean when they are trying to learn it.

In many situations, Polish speakers would strongly prefer zapamiętać for the act of committing something to memory.

Yes.

Polish present-tense forms with verbs like musieć often refer to a current obligation about a future action.

So Muszę zapamiętać ten adres can mean:

• I need to memorize this address now
• I have to remember this address for later
• I must make sure I learn this address

The obligation exists now, while the action of memorizing may happen immediately or in the near future.

Not exactly.

• Muszę zapamiętać ten adres. = strong necessity, I have to / I must
• Powinienem zapamiętać ten adres. = weaker, I should remember / I ought to memorize

So muszę expresses obligation or necessity, while powinienem expresses advice, expectation, or weaker duty.

In many contexts, ten can correspond to English this, and sometimes to that, depending on the situation.

In modern everyday Polish, ten is very common and often functions as the basic demonstrative determiner.

So:

• ten adres can mean this address
• in some contexts it may be translated differently depending on what is already known in the conversation

Since you said the meaning is already shown to the learner, the key grammar point is that ten agrees with adres in gender, number, and case.

The dictionary form is exactly zapamiętać. In Polish, dictionary verb forms are infinitives, and they often end in:

• -ć
• -c
• occasionally other patterns in spelling, though -ć is very common

So zapamiętać is the infinitive, just like English to memorize or to remember in dictionary form.

In actual sentences after muszę, Polish uses the infinitive without any extra word:

• muszę zapamiętać
• not muszę to zapamiętać in the infinitive sense of English to