Barna ler når hunden prøver å spise smulene som ligger under stolen.

Barna is the normal definite plural form of barn (child / children) in Bokmål.

• et barn = a child
• barn = children
• barna = the children

This is one of those very common Norwegian patterns where a neuter noun can take -a in the definite plural. You may also encounter barnene, but barna is extremely common and natural in everyday Norwegian.

Norwegian usually does not use a separate verb like are in the present progressive the way English does.

So:

• Barna ler = The children laugh / are laughing

The present tense ler can cover both a general present and an action happening right now, depending on context.

Ler is the present tense of the verb å le (to laugh).

A few forms:

• å le = to laugh
• ler = laugh / is laughing
• lo = laughed
• har ledd = have/has laughed

In the sentence, Barna ler simply means The children laugh / are laughing.

Here når means when, but in many contexts it can also feel like whenever.

In this sentence:

• Barna ler når hunden prøver å spise smulene ...
• The children laugh when the dog tries to eat the crumbs ...

Because the whole sentence describes a situation, English might interpret it as either a specific when or a more habitual whenever, depending on context. Norwegian når often works for both.

Hunden is the definite form, meaning the dog.

• en hund = a dog
• hunden = the dog

The sentence is talking about a specific dog, not just any dog, so Norwegian uses the definite form.

This is a very common Norwegian pattern:

• prøver = tries
• å spise = to eat

Together:

• prøver å spise = tries to eat

After many verbs in Norwegian, you use å + infinitive. So:

• å prøve = to try
• prøver å gjøre noe = tries to do something

Examples:

• Hun prøver å sove. = She is trying to sleep.
• Vi prøver å lære norsk. = We are trying to learn Norwegian.

Å is the infinitive marker, like English to before a verb.

So:

• spise = the verb stem / infinitive form
• å spise = to eat

After prøver, Norwegian normally uses å + infinitive:

• hunden prøver å spise = the dog tries to eat

Smulene is the definite plural form of smule (crumb).

• en smule = a crumb
• smuler = crumbs
• smulene = the crumbs

So the sentence refers to specific crumbs, not just crumbs in general.

It describes smulene (the crumbs).

So the structure is:

• smulene = the crumbs
• som ligger under stolen = that are lying under the chair

Together:

• smulene som ligger under stolen = the crumbs that are under the chair

This is a relative clause, introduced by som, which often means that, which, or who in English.

Som is the normal relative pronoun in Norwegian.

It links a noun to extra information about that noun:

• smulene som ligger under stolen
• the crumbs that are under the chair

Other examples:

• mannen som snakker = the man who is speaking
• boka som ligger der = the book that is lying there

So here, som introduces the clause that tells us which crumbs we mean.

Ligge means to lie or to be lying / be located. In Norwegian, it is very common to use position verbs where English might simply say is/are.

So:

• smulene ligger under stolen literally = the crumbs are lying under the chair
• natural English = the crumbs are under the chair

Norwegian often prefers:

• ligge for things lying
• stå for things standing
• sitte for things/people sitting

This is very natural Norwegian usage.

Because stolen means the chair, while stol by itself is not a complete noun form in Bokmål.

The forms are:

• en stol = a chair
• stolen = the chair

So:

• under stolen = under the chair

Norwegian usually attaches definiteness to the end of the noun.

Yes, under is a preposition meaning under / beneath.

Unlike languages with case systems, modern Norwegian does not change the noun form because of the preposition in the way German does, for example. You simply use the noun in the appropriate indefinite or definite form:

• under en stol = under a chair
• under stolen = under the chair

Yes. Norwegian main clauses and subordinate clauses have different word order patterns.

Main clause:

• Barna ler
• subject + verb

Subordinate clause introduced by når:

• når hunden prøver å spise smulene
• conjunction + subject + verb

In a subordinate clause, Norwegian normally keeps the subject before the verb. So this part is very regular.

Compare:

• Main clause: Hunden prøver å spise smulene.
• Subordinate clause: ... når hunden prøver å spise smulene.

Yes. You could say:

• Når hunden prøver å spise smulene som ligger under stolen, ler barna.

That means the same thing. But when a subordinate clause comes first in Norwegian, the main clause follows normal V2 word order, so the verb comes before the subject:

• ..., ler barna not
• ..., barna ler

That word order change is very important in Norwegian.

It is actually quite close to English:

• Barna = The children
• ler = laugh / are laughing
• når = when
• hunden = the dog
• prøver å spise = tries to eat
• smulene = the crumbs
• som ligger under stolen = that are lying under the chair

So the sentence is built in a way that should feel fairly familiar to an English speaker. The main things to notice are:

1. Norwegian uses noun endings for the
2. Norwegian often uses simple present where English might use are laughing
3. Norwegian uses som for relative clauses
4. Norwegian often uses ligger where English may just say are