Muszę obrać ziemniaki przed obiadem.

Musieć is the dictionary form, meaning to have to / must.

In the sentence, you need the 1st person singular form, because the speaker is saying I must:

• musieć = to have to
• muszę = I have to / I must

So:

• Muszę obrać ziemniaki = I have to peel the potatoes

Polish verbs change form depending on the person, much more than English verbs do.

After verbs like muszę, Polish normally uses the infinitive directly, without any extra word.

So:

• muszę obrać = I must peel
• literally, it is just must peel

English usually says have to peel or must peel, but Polish does not need a separate word corresponding to English to here.

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

• obierać = imperfective
• obrać = perfective

In this sentence, obrać is used because the speaker means a complete task: peeling the potatoes so that the job gets done.

• Muszę obrać ziemniaki = I need to peel the potatoes, meaning finish peeling them
• Muszę obierać ziemniaki would sound more like I have to be peeling potatoes, or I have to peel potatoes in general / repeatedly, depending on context

So obrać is the natural choice when talking about a single task that needs to be completed before the meal.

Because ziemniaki is the direct object of obrać.

The singular noun is:

• ziemniak = potato

The plural is:

• ziemniaki = potatoes

Here, the word is in the accusative plural, because it is the thing being peeled. For this noun, the accusative plural looks the same as the nominative plural:

• nominative: ziemniaki
• accusative: ziemniaki

So even though the form looks unchanged, it is still functioning as the object of the verb.

Because the preposition przed requires the instrumental case when it means before or in front of.

The base form is:

• obiad = dinner / lunch, depending on context

The instrumental singular is:

• obiadem

So:

• przed obiadem = before dinner / before lunch

This is a very common pattern:

• przed szkołą = in front of the school / before school
• przed pracą = before work
• przed snem = before sleep

It can be tricky, because obiad does not match perfectly with one English meal word.

In Polish, obiad usually means the main cooked meal of the day, often eaten in the afternoon. Depending on the household and the context, English might translate it as:

• lunch
• dinner

So the exact English translation depends on the situation, but the Polish word itself is completely normal here.

Polish often drops subject pronouns when they are not needed.

The verb form muszę already tells you the subject is I, so ja is unnecessary.

• Muszę obrać ziemniaki = I must peel the potatoes

You could say Ja muszę obrać ziemniaki, but that would usually add emphasis, for example:

• Ja muszę obrać ziemniaki, a ty nakryj do stołu. = I have to peel the potatoes, and you set the table.

So the version without ja is the normal neutral one.

Yes. Polish word order is more flexible than English word order.

The sentence:

• Muszę obrać ziemniaki przed obiadem.

is a neutral, natural order.

But you could also say:

• Przed obiadem muszę obrać ziemniaki.
• Ziemniaki muszę obrać przed obiadem.

These versions are still grammatical, but the emphasis changes:

• Przed obiadem first emphasizes the time
• Ziemniaki first emphasizes what must be peeled

So the original version is a good default choice.

Yes. Obrać often means to peel or to skin something, especially food.

Examples:

• obrać ziemniaki = peel potatoes
• obrać jabłko = peel an apple
• obrać marchewkę = peel a carrot

So in this sentence, obrać ziemniaki is a very natural everyday expression.

A rough English-friendly guide would be:

MOO-sheh OH-brach్ zhyem-NYAH-kee pshed oh-BYAH-dem

A few useful pronunciation points:

• sz sounds like sh
• ć is a soft sound, a bit like a very soft ch
• zi in ziemniaki is soft, not like English zoo
• rz in przed sounds like the zh sound in measure
• ą and ę are nasal vowels, though in everyday speech they may sound less strongly nasal depending on position

You do not need perfect pronunciation right away, but recognizing sz, rz, and ć is very helpful.

Yes, in many contexts.

Both can mean potatoes:

• ziemniaki = the most standard and widely used word
• kartofle = also common, but more regional or stylistically marked depending on where you are

So:

• Muszę obrać kartofle przed obiadem.

is also possible, but ziemniaki is the safer neutral word for learners to use.