Bukselengden er veldig lang.

Because Norwegian usually writes compound nouns as a single word.

Here, bukselengden is built from:

• bukse = pants / trousers
• lengde = length

So bukselengde means pants length or trouser length.

Then Norwegian adds the definite ending to the noun, giving bukselengden = the pants length / the trouser length.

This is very normal in Norwegian. English often uses separate words where Norwegian prefers one compound word.

In Norwegian, the is often not a separate word. Instead, it is added to the end of the noun.

So:

• en bukselengde = a pants length
• bukselengden = the pants length

That means the -en ending is doing the job that the does in English.

The dictionary form is en bukselengde.

That breaks down as:

• en = a
• bukselengde = pants length / trouser length

In the sentence, it appears in the definite singular form:

• bukselengden = the pants length

So if you wanted to look it up, you would normally look for bukselengde.

Because the adjective agrees with the noun, and bukselengden is a singular common-gender noun.

So the correct form is:

• lang for singular common gender
• langt for singular neuter
• lange for plural or certain definite contexts

Examples:

• En vei er lang. = A road is long.
• Et bord er langt. = A table is long.
• Buksene er lange. = The pants are long.

Since bukselengden is singular and common gender, lang is correct.

Veldig means very.

In this sentence:

• veldig lang = very long

Veldig does not change form here. It is an adverb that modifies the adjective lang.

So:

• veldig lang = very long
• veldig kort = very short
• veldig stor = very big

It works much like very in English.

This is the normal word order for a basic Norwegian main clause:

• subject + verb + rest

So here:

• Bukselengden = subject
• er = verb
• veldig lang = description of the subject

This is the same basic pattern as in English:

• The pants length is very long.

Norwegian main clauses usually put the finite verb in the second position, and this sentence follows that rule.

That is a very common thing for English speakers to notice.

In Norwegian, bukse can refer to one pair of pants/trousers, even though English usually uses a plural word:

• en bukse = a pair of pants / a pair of trousers

The plural is:

• bukser = pants / trousers, or multiple pairs

In compounds, Norwegian normally uses the singular stem, so bukselengde is completely normal.

It is understandable and grammatically fine, especially if you are specifically talking about the length measurement of the pants.

But in everyday situations, Norwegians might often say something more direct, such as:

• Buksene er for lange. = The pants are too long.
• Denne buksa er for lang. = These pants / this pair of pants is too long.

So the original sentence sounds most natural when the topic is specifically the length of the pants, not just the pants in general.

Yes. Norwegian lang can describe both:

• physical length: en lang bukse, en lang vei
• duration: en lang dag, en lang film

In Bukselengden er veldig lang, it clearly refers to physical length, not time.

The context makes that obvious.