Sjøsyke kan reduseres.

Here, sjøsyke is a noun meaning seasickness.

That can be confusing because sjøsyk is also an adjective meaning seasick, and one of its forms is sjøsyke:

• Jeg er sjøsyk = I am seasick
• De er sjøsyke = They are seasick

So sjøsyke can be either:

• a noun: seasickness
• an adjective form: seasick in certain contexts

In Sjøsyke kan reduseres, it is clearly the noun because it is the subject of the sentence.

Because Norwegian usually writes this kind of idea as one compound word.

English often uses more spaces than Norwegian does. So where English has seasickness, Norwegian has sjøsyke as one word.

This is very normal in Norwegian:

• togstasjon = train station
• barnebok = children’s book
• sjøsyke = seasickness

Because sjøsyke is being used in a general, uncountable sense, like seasickness in English.

Compare:

• Sjøsyke kan reduseres = seasickness in general can be reduced
• Sjøsyken kan reduseres = the seasickness can be reduced, meaning a more specific case

So the version without an article sounds natural when talking about the condition in general.

Kan is the modal verb can.

In this sentence, it expresses possibility:

• Sjøsyke kan reduseres = seasickness can be reduced

It does not mean permission here. It is closer to:

• is possible to reduce
• may be reduced
• can be reduced

Because after a modal verb like kan, Norwegian normally uses the verb without å.

So:

• kan reduseres = can be reduced

Not:

• kan å reduseres

This is the normal pattern with modal verbs such as:

• kan
• må
• skal
• vil
• bør

For example:

• Jeg kan svømme = I can swim
• Du må gå = You must go

The -s shows the passive.

So:

• redusere = to reduce
• reduseres = to be reduced

That means the sentence is focusing on seasickness as the thing affected, not on who is doing the reducing.

Compare:

• Man kan redusere sjøsyke = One/you can reduce seasickness
• Sjøsyke kan reduseres = Seasickness can be reduced

This -s passive is common in Norwegian, especially in neutral or informative language.

After kan, it functions as the verb form that goes with a modal verb, so in meaning it is be reduced.

The tricky part is that the Norwegian -s passive often has the same form in places where English would distinguish different forms more clearly.

So for learning purposes, the easiest way to understand this sentence is:

• kan reduseres = can be reduced

You do not need to translate it word-for-word as a present tense.

Yes, it is a passive sentence.

Passive:

• Sjøsyke kan reduseres = Seasickness can be reduced

Active:

• Man kan redusere sjøsyke = One/you can reduce seasickness

The passive version is useful when the important thing is the result or the general fact, not who does it.

Yes, that is also possible.

Both of these are understandable and natural:

• Sjøsyke kan reduseres
• Sjøsyke kan bli redusert

A rough difference is:

• kan reduseres sounds a bit more compact, neutral, and informational
• kan bli redusert sounds a bit more explicit about the change happening

In many contexts, the difference is small.

Because Norwegian main clauses usually follow the verb-second rule.

That means the finite verb comes in the second position. Here:

1. Sjøsyke = first element
2. kan = finite verb in second position
3. reduseres = the other verb comes later

So the structure is:

• subject + finite verb + main verb

You can see the same pattern in other sentences:

• Jeg kan hjelpe
• Han skal reise

If another element comes first, the finite verb still stays second:

• Ofte kan sjøsyke reduseres = Often, seasickness can be reduced

A useful guide is:

• sj sounds like English sh
• ø has no exact English equivalent, but it is similar to the vowel in French deux or German schön
• y also has no exact English equivalent; it is like French u or German ü
• the stress is on the first syllable: SJØ-sy-ke
• the final e is a weak sound, like uh

So the hardest parts for English speakers are usually ø and y, because both are rounded front vowels that English does not really have.

Yes, it sounds natural, especially in informational, medical, or advice contexts.

It has a slightly neutral, written style because it uses the passive. That makes it sound like something you might read in:

• a health article
• travel advice
• an information leaflet

A more direct everyday-style version could be:

• Man kan redusere sjøsyke
• Du kan redusere sjøsyke ved å ...

So the given sentence is natural; it is just a bit more impersonal and factual in tone.