Vi ler høyt når vi ser en morsom film.

Because Norwegian usually states the subject in each clause.

This sentence has:

• a main clause: Vi ler høyt
• a subordinate clause: når vi ser en morsom film

Each clause needs its own subject, so vi appears in both parts.

In English, you also usually do this:

• We laugh loudly when we watch a funny film.

You would not normally say:

• We laugh loudly when watch a funny film.

So Norwegian is working the same way here.

Høyt means loudly or out loud in this sentence.

It comes from høy, which usually means high or tall, but as an adverb høyt can describe sound level:

• snakke høyt = speak loudly
• le høyt = laugh loudly
• rope høyt = shout loudly

So Vi ler høyt means that the laughter is audible and strong, not just that we find something funny.

In Norwegian, present-tense verbs do not change according to the subject the way they do in English.

So:

• jeg ler = I laugh
• du ler = you laugh
• vi ler = we laugh
• de ler = they laugh

And:

• jeg ser = I see
• vi ser = we see

This is simpler than English, where you have forms like I see but he sees. In Norwegian, the present-tense form stays the same for all persons.

Når means when and is used for things that happen:

• regularly
• generally
• repeatedly
• in the present or future

So når vi ser en morsom film means when we watch a funny film in the sense of whenever that happens.

A very common contrast is:

• når = when, whenever
• da = when, at that time, for a specific event in the past

Examples:

• Jeg smiler når jeg er glad. = I smile when I am happy.
• Jeg smilte da jeg så filmen. = I smiled when I saw the film.

In your sentence, når fits because it describes a general situation.

Because in a subordinate clause introduced by når, Norwegian normally uses subject + verb order:

• når vi ser
• fordi jeg liker
• at hun kommer

So:

• når vi ser en morsom film = correct

But ser vi is the kind of order you often get in:

• questions: Ser vi filmen?
• main clauses after another element comes first: I dag ser vi filmen.

So the clause after når keeps the more basic order:

• når + subject + verb

Because film is an en-word in Norwegian:

• en film

Adjectives must agree with the noun they describe. For an en-word in singular indefinite form, the adjective usually has its basic form:

• en morsom film

Compare:

• en morsom bok = a funny book
• et morsomt bilde = a funny picture

So:

• morsom is used with en nouns
• morsomt is used with et nouns

That is why en morsom film is correct.

It actually is already in the correct agreement form for this noun phrase.

In Norwegian, adjective endings depend on the noun pattern. Here you have:

• singular
• indefinite
• an en-word

So the adjective takes its base form:

• en morsom film

Compare:

• et morsomt teaterstykke = a funny play
• morsomme filmer = funny films
• den morsomme filmen = the funny film

So morsom does not get an extra ending here because this specific noun phrase does not require one.

In this sentence, English often translates ser as watch:

• when we watch a funny film

But the Norwegian verb is still se, which can mean both see and watch, depending on context.

Examples:

• Jeg ser en bil. = I see a car.
• Jeg ser en film. = I’m watching a film / I watch a film.

So learners should not expect Norwegian to always use separate verbs the way English often does.

Both are natural, but they are slightly different.

• Vi ler = We laugh / We are laughing
• Vi ler høyt = We laugh loudly / We laugh out loud

Adding høyt makes the image stronger. It emphasizes that the laughter is noticeable and audible.

So the sentence without høyt would still be correct, but høyt adds extra detail.

Yes. The Norwegian present tense often covers both:

• something happening now
• a general truth or repeated habit

So Vi ler høyt når vi ser en morsom film can mean:

• We laugh loudly when we watch a funny film
• We laugh out loud whenever we see a funny film

The exact interpretation depends on context. Without extra context, it often sounds like a general statement about what usually happens.

The t is there because høyt is an adverb form.

Very roughly, høyt sounds something like:

• hoyt, but with the Norwegian vowel ø, which does not exist in standard English

A few useful points:

• øy is a vowel combination you will need to get used to
• the final t is pronounced
• the word is one syllable in careful speech

The spelling reflects that this is not the adjective høy, but the adverb høyt:

• en høy mann = a tall man
• han snakker høyt = he speaks loudly

So the t helps mark the adverb form here.