Mam zamiar kupić papierowe torby i jedną plastikową butelkę na wodę.

Mam zamiar means I intend to or I am planning to. It suggests a plan or intention, not just a desire.

Compare:

• Chcę kupić... = I want to buy...
• Mam zamiar kupić... = I intend / plan to buy...

So mam zamiar often sounds a bit more deliberate than chcę.

Also, mam zamiar is normally followed by an infinitive, as in mam zamiar kupić.

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

• kupić = perfective = to buy, with the idea of completing the action
• kupować = imperfective = to be buying / to buy regularly / to buy in a more ongoing or repeated sense

In this sentence, the speaker means a specific planned purchase, so kupić is the natural choice.

• Mam zamiar kupić... = I intend to buy...
• Mam zamiar kupować... would sound more like I intend to buy regularly / repeatedly

They are in the accusative case, because they are the direct objects of kupić.

The verb kupić answers the question buy what?

• papierowe torby = paper bags
• jedną plastikową butelkę na wodę = one plastic water bottle

In Polish, direct objects often go into the accusative.

Because the two nouns are doing different things grammatically:

• torby is plural
• butelkę is singular accusative

Here are the base forms:

• torba = bag
• butelka = bottle

Now in the sentence:

• papierowe torby = plural direct object
• jedną plastikową butelkę = singular direct object

For feminine nouns:

• nominative singular: butelka
• accusative singular: butelkę

So butelka changes to butelkę because it is a feminine singular direct object.

Meanwhile torby is just the plural form needed for bags.

Because adjectives in Polish must agree with the noun they describe in:

• gender
• number
• case

So:

• papierowe torby

  • torby is plural
  • the adjective must also be plural: papierowe

• jedną plastikową butelkę

  • butelkę is feminine singular accusative
  • the adjective must match: plastikową

So the different endings are not random; they show grammatical agreement.

Jedną literally means one.

Polish does not have articles like a/an or the, so jedną is not just a normal article. It specifically adds the idea of one.

So:

• plastikową butelkę = a plastic bottle
• jedną plastikową butelkę = one plastic bottle

In this sentence, jedną makes the quantity explicit.

Also, jedną is the feminine accusative form of jeden because it matches butelkę.

Because Polish generally does not use articles.

English needs words like:

• a
• an
• the
• sometimes some

Polish usually leaves that information to context.

So:

• papierowe torby can mean paper bags, some paper bags, or the paper bags, depending on context
• jedną plastikową butelkę clearly means one plastic bottle

This is very normal in Polish, even though it feels unusual to English speakers at first.

Because na wodę means for water or intended for water.

So butelka na wodę is a water bottle in the sense of a bottle used to carry water.

Compare:

• butelka na wodę = a bottle for water
• butelka z wodą = a bottle with water inside it

So in this sentence, the meaning is about the type/purpose of the bottle, not what is inside it right now.

Because na can require different cases, and here it takes the accusative.

Base form:

• woda = water

After na in this kind of expression:

• na wodę = for water

This use of na + accusative often expresses purpose or intended use.

So butelka na wodę literally works like a bottle for water.

No, Polish word order is fairly flexible, because endings show grammatical relationships.

The given sentence:

Mam zamiar kupić papierowe torby i jedną plastikową butelkę na wodę.

is a natural, neutral order.

But other orders are possible for emphasis, for example:

• Papierowe torby i jedną plastikową butelkę na wodę mam zamiar kupić.

That version puts more focus on what the speaker intends to buy.

So the original word order is the most neutral and standard, but it is not the only possible one.