Nie zadzwonię drugi raz, bo telefon jest rozładowany.

Because Polish usually drops subject pronouns when they are clear from the verb ending.

• zadzwonię = I will call / I will phone
• the ending -ę already tells you the subject is I

So:

• Nie zadzwonię = I won’t call
• Ja nie zadzwonię also works, but ja is usually added only for emphasis, contrast, or clarity.

For example:

• Ja nie zadzwonię, ale on zadzwoni. = I won’t call, but he will.

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

• dzwonić = to be calling / to call in an ongoing, repeated, or habitual sense
• zadzwonić = to call in the sense of making one complete call

In this sentence, the speaker means one call, so Polish uses the perfective verb:

• zadzwonię = I will call (once / successfully place a call)

Compare:

• Zadzwonię jutro. = I’ll call tomorrow.
• Będę dzwonić cały wieczór. = I’ll be calling all evening.

So zadzwonię is the natural choice here because it refers to one future action.

Because in Polish, perfective verbs do not have a true present tense. Their “present-looking” forms are used with future meaning.

So:

• zadzwonię literally looks like a present form
• but because zadzwonić is perfective, it means I will call

This is very common in Polish:

• napiszę = I will write
• zrobię = I will do / make
• powiem = I will say

By contrast, imperfective verbs form the future differently:

• będę dzwonić = I will be calling / I will call
  but with a different nuance than zadzwonię

In Polish, nie is normally written separately from finite verb forms.

So:

• nie zadzwonię = correct
• nie jest = correct

This is just the standard spelling rule for verbs.

Compare:

• Nie wiem. = I don’t know.
• Nie zrobię tego. = I won’t do that.

Learners sometimes expect it to be attached, but with verbs it is usually separate.

Drugi raz means a second time or again for the second time.

Literally:

• drugi = second
• raz = time / occasion

So:

• Nie zadzwonię drugi raz = I won’t call a second time

It is a very common Polish way to talk about repeated actions:

• Pierwszy raz = the first time
• Drugi raz = the second time
• Trzeci raz = the third time

Both can exist, but they mean slightly different things.

• drugi raz = a second time
• drugim razem = on the second occasion / next time depending on context

In this sentence, the speaker means I won’t call again a second time, so drugi raz is the natural phrase.

Compare:

• Nie zrobię tego drugi raz. = I won’t do that a second time.
• Drugim razem zrobię to lepiej. = Next time / the second time, I’ll do it better.

So drugi raz is about repetition of the action, while drugim razem often points more to the occasion.

It is in the accusative.

Why? Because Polish often uses the accusative in expressions answering questions like how many times?

• raz is a masculine inanimate noun
• for many masculine inanimate nouns, accusative = nominative
• so raz stays raz
• drugi also has the accusative form drugi here

That is why you see:

• drugi raz
• pierwszy raz
• ostatni raz

Even if you are not ready to analyze the full grammar yet, it is useful to learn drugi raz as a fixed expression.

Yes. Po raz drugi also means for the second time.

So these are both possible:

• Nie zadzwonię drugi raz.
• Nie zadzwonię po raz drugi.

The version with po raz drugi can sound a bit more formal, deliberate, or emphatic.
Drugi raz is very natural in everyday speech.

Compare:

• To już drugi raz! = That’s already the second time!
• To już po raz drugi! = That’s already for the second time!
  slightly more formal or rhetorical

Bo means because and is very common in spoken and everyday Polish.

So:

• Nie zadzwonię drugi raz, bo telefon jest rozładowany. = I won’t call a second time because the phone is dead/out of battery.

Ponieważ also means because, but it sounds more formal or written.

Compare:

• Nie przyjdę, bo jestem zmęczony. = everyday, natural
• Nie przyjdę, ponieważ jestem zmęczony. = more formal

For normal conversation, bo is usually the best choice.

Because in Polish, a clause introduced by bo is normally separated by a comma.

So:

• Nie zadzwonię drugi raz, bo telefon jest rozładowany.

This is standard Polish punctuation.

You will see the same with many conjunctions introducing another clause:

• Zostanę w domu, bo pada. = I’ll stay home because it’s raining.

Rozładowany literally means discharged.

With devices, batteries, or phones, it usually means:

• out of battery
• dead
• flat

So:

• telefon jest rozładowany literally = the phone is discharged
• natural English = the phone is dead / out of battery

This adjective comes from the verb rozładować / rozładowywać = to discharge.

Polish often says a phone is rozładowany, even though in English we may think more specifically of the battery being dead.

So Polish can say:

• Telefon jest rozładowany. = The phone is dead / out of battery.
• Bateria jest rozładowana. = The battery is discharged.

Both are possible, but talking about the phone directly is very natural in Polish.

Because it agrees with telefon, which is:

• masculine
• singular

Polish adjectives must agree with the noun in gender, number, and case.

So:

• telefon → masculine singular
• rozładowany → masculine singular form

Compare:

• telefon jest rozładowany = masculine
• bateria jest rozładowana = feminine
• urządzenie jest rozładowane = neuter

This agreement is a basic and very important Polish pattern.

In modern everyday Polish, yes, very often telefon in a sentence like this will be understood as a mobile phone / cell phone, especially because of rozładowany.

A landline phone is not normally described as rozładowany, so context strongly suggests a mobile phone.

If needed, Polish can be more specific:

• telefon komórkowy = mobile phone / cell phone

But very often just telefon is enough.

It is similar, but not exactly the same.

• Nie zadzwonię drugi raz focuses on one complete call not happening
• Nie będę dzwonić drugi raz uses the imperfective future and can sound more like I’m not going to be calling again / I won’t be making another attempt to call

So:

• zadzwonię = one completed call
• będę dzwonić = the action/process of calling

In many contexts, both could be translated similarly, but Nie zadzwonię drugi raz is more natural if you mean I’m not making another call.

Yes. Polish word order is fairly flexible, though not completely free. The most neutral order here is:

• Nie zadzwonię drugi raz, bo telefon jest rozładowany.

But other orders are possible for emphasis:

• Bo telefon jest rozładowany, nie zadzwonię drugi raz.
• Nie zadzwonię, bo telefon jest rozładowany, drugi raz.
  this one sounds awkward in normal speech

So although Polish allows movement, not every rearrangement sounds natural.
For learners, the original order is the safest and most idiomatic.

A rough guide is:

• Nie ≈ nye
• zadzwonię ≈ za-dzvo-nye
• drugi raz ≈ DROO-gi rass
• bo telefon jest rozładowany ≈ bo te-LE-fon yest roz-wa-do-VA-nih

A few helpful points:

• dz is pronounced together, like the ds sound in kids
• w in Polish sounds like English v
• ń is a soft n, similar to the ny in canyon
• rz usually sounds like zh as in measure
• ł sounds like English w

So zadzwonię can feel difficult at first, but it helps to break it into parts:

• za + dzwo + nię

Then say it smoothly: zadzwonię.