Planen kan mislykkes.

Because -en is the usual definite ending for many masculine nouns in Norwegian.

• en plan = a plan
• planen = the plan

So Planen kan mislykkes literally starts with The plan...

Norwegian often puts the definite article at the end of the noun instead of using a separate word like the.

Kan is the present tense of å kunne, and here it means can, may, or might in the sense of possibility.

In this sentence, kan does not mean physical ability. A plan cannot "be able" in the human sense. Instead, it means something like:

• The plan can fail
• The plan may fail
• The plan might fail

So kan often covers both can and may/might, depending on context.

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

So:

• å mislykkes = to fail
• kan mislykkes = can fail

This is similar to English:

• to fail
• can fail

You do not say can to fail in English, and you do not say kan å mislykkes in Norwegian.

Mislykkes means to fail, to be unsuccessful, or to not succeed.

In this sentence, it means that the plan might not work out.

A useful nuance:

• mislykkes often suggests that something does not succeed
• it can sound a little more formal or abstract than some everyday alternatives

So Planen kan mislykkes is a very natural way to say The plan can fail or The plan may not succeed.

It looks like one, but in this case you should learn å mislykkes as a whole verb meaning to fail.

Norwegian does have -s forms that can be passive, but mislykkes is commonly used as an independent verb with the meaning fail / be unsuccessful.

So for a learner, the safest approach is:

• treat å mislykkes as the dictionary form
• do not try to break it into smaller parts in normal use

In other words, here mislykkes is best understood simply as fail.

No, this is basic Norwegian main-clause word order:

• Planen = subject
• kan = finite verb
• mislykkes = main verb

So the pattern is:

subject + finite verb + infinitive/main verb

That is very similar to English:

• The plan can fail

This is a simple declarative sentence.

Yes, but it means something different.

• Planen kan mislykkes = The plan can/may fail
  This expresses possibility.
• Planen mislykkes = The plan fails / is failing
  This sounds like a statement of fact, not just possibility.

So kan is important because it changes the meaning from it fails to it may fail.

Sometimes, yes, but the nuance can be different.

• å feile can mean to fail
• å mislykkes also means to fail / not succeed

In many contexts, both are possible, but mislykkes often fits especially well when talking about whether something succeeds or not.

So:

• Planen kan mislykkes = very natural
• Planen kan feile = also possible in some contexts, but not always exactly the same in tone or usage

If you are unsure, mislykkes is a good choice for the idea of not succeeding.

A rough pronunciation guide for an English speaker is:

PLAH-nen kahn mis-LYK-es

A few notes:

• planen: the first a is broad, closer to ah than the English a in plan
• kan: also with an ah sound
• mislykkes: the stress is mainly on lykk
• y in Norwegian is not an English y sound; it is a rounded front vowel, which can be tricky for English speakers

You do not need perfect pronunciation at first, but be careful especially with the vowel in lykk.

It can mean both, depending on context.

In this sentence, the most natural English translation is often:

• The plan may fail
• The plan might fail
• The plan can fail

Why? Because a plan is not really doing an ability action. The sentence is about possibility, not skill or capacity.

So when you see kan, always ask:

• is this ability?
• or is it possibility?

Here it is clearly possibility.

Yes, it is completely natural.

Planen kan mislykkes is short, clear, and idiomatic. It is the kind of sentence you could see in:

• everyday speech
• news writing
• business discussion
• academic or formal contexts

It is a good example of a very common Norwegian structure: definite noun + modal verb + infinitive.