Nurt ma wpływ na kajak.

Ma is the 3rd person singular form of the verb mieć = to have.

So:

• mieć = to have
• ma = he/she/it has

In this sentence, nurt is singular, so we use ma:

• Nurt ma wpływ... = The current has an influence...

Both are possible.

• Nurt ma wpływ na kajak = The current has an effect on the kayak
• Nurt wpływa na kajak = The current affects the kayak

The version with ma wpływ na is a noun-based expression:

• wpływ = influence, effect
• mieć wpływ na = to have an influence/effect on

It is a very common Polish structure. It can sound a bit more formal or analytical than simply using a verb.

Nurt is in the nominative case because it is the subject of the sentence.

It is the thing doing the action:

• Nurt ma wpływ...
• The current has an effect...

So nurt is the grammatical subject.

Kajak is in the accusative case because the phrase is mieć wpływ na coś = to have an effect on something.

The preposition na here requires the accusative.

For masculine inanimate nouns, the accusative singular is often identical to the nominative singular. That is why you still see kajak and not a different form.

So:

• nominative: kajak
• accusative: kajak

Same spelling, different grammatical role.

Because this na is part of the fixed expression wpływ na coś / mieć wpływ na coś.

Here, na takes the accusative, not the locative.

Compare:

• wpływ na kajak = effect on the kayak
• na kajaku = on the kayak / in a kayak contextually, using the locative

So:

• na kajak here does not mean physical movement onto a kayak
• it means on the kayak in the sense of affecting it

No. Na can take different cases depending on meaning.

Most commonly:

• accusative: direction, target, or certain fixed expressions
• locative: location

Examples:

• Idę na most. = I’m going onto/to the bridge.
• Jestem na moście. = I’m on the bridge.

In your sentence, na is used in a fixed expression:

• mieć wpływ na coś

So it takes the accusative.

Polish normally has no articles like a or the.

So:

• nurt can mean a current or the current
• kajak can mean a kayak or the kayak

The exact meaning depends on context.

If Polish speakers need to be more specific, they can use other words such as:

• ten kajak = this/the kayak
• ten nurt = this/the current

But in a normal sentence, articles are simply not required.

Yes, if you mean a water current, especially in a river.

That is important because English current has several meanings. In Polish:

• nurt = current of water, flow of a river
• prąd = current in electricity, and also sometimes water current in some contexts

For a sentence about a kayak on water, nurt is a very good and natural choice.

Yes, it is grammatical and understandable.

However, many speakers might also say:

• Nurt wpływa na kajak.
• Nurt oddziałuje na kajak.

The version with ma wpływ na is still natural, but it sounds a bit more like describing an effect than a simple everyday action.

So the sentence is fine; it is just one of several natural ways to express the idea.

Yes. Polish word order is fairly flexible because case endings show grammatical roles.

The neutral order here is:

• Nurt ma wpływ na kajak.

But you could also change it for emphasis, for example:

• Na kajak wpływ ma nurt.
• Wpływ na kajak ma nurt.

These alternatives are more marked and would usually be used for emphasis or style. For a learner, the original order is the safest and most neutral.

A rough pronunciation guide:

• nurt ≈ noort
• ma ≈ mah
• wpływ ≈ something like vpwihf or fpwihf at normal speed
• na ≈ nah
• kajak ≈ KAI-yak

A few useful points:

• ó in wpływ sounds like u
• ł sounds like English w
• word-final voiced consonants often devoice, so wpływ is not pronounced with a strong final English v

The hardest word here for many learners is wpływ, because Polish allows consonant clusters that feel unusual in English.