Saksbehandlingstiden i bostedskommunen er lang.

Because Norwegian usually writes compound nouns as one word.

• saksbehandlingstid = sak
  • behandling
    • tid
• bostedskommune = bosted
  • kommune

This is very normal in Norwegian, especially in formal or administrative language. English often uses several words where Norwegian prefers one compound.

A useful rule: the last part is the main noun. So:

• saksbehandlingstid is a kind of tid (time)
• bostedskommune is a kind of kommune (municipality)

The ending -en is the definite article, roughly like the in English.

So:

• saksbehandlingstid = case-processing time
• saksbehandlingstiden = the case-processing time

and

• bostedskommune = municipality of residence
• bostedskommunen = the municipality of residence

In Norwegian, the definite article is often attached to the noun instead of being a separate word.

Because both noun phrases are specific.

The sentence is talking about:

• the processing time
• in the municipality of residence

So Norwegian marks both nouns as definite:

• saksbehandlingstiden
• bostedskommunen

This is completely normal. English also does this: The processing time in the municipality of residence is long.

Because lang is a predicative adjective after er, and it has to agree with the noun it describes.

The head noun is tid, which is singular and non-neuter/common gender in Bokmål. So the adjective stays in its basic form:

• Tiden er lang.

Compare:

• Huset er langt. = neuter singular
• Dagene er lange. = plural

So in this sentence, lang is the correct form.

I means in here.

With places such as cities, countries, and municipalities, Norwegian often uses i to mean in/within that area:

• i Oslo
• i Norge
• i kommunen

So i bostedskommunen means in the municipality of residence or within your home municipality.

Bostedskommune is a formal administrative word. It means the municipality where a person lives or is officially registered as living.

A more everyday way to express the same idea might be:

• kommunen du bor i = the municipality you live in

So bostedskommune is correct, but it sounds official and bureaucratic.

Yes:

• sak = case, matter
• behandling = handling, processing, treatment
• tid = time

So saksbehandlingstid literally means something like case-processing time.

In practice, it means the time it takes for a case/application to be processed. This kind of compound is very common in public-sector Norwegian.

The subject is the whole noun phrase:

Saksbehandlingstiden i bostedskommunen

Inside that phrase:

• saksbehandlingstiden is the main noun
• i bostedskommunen tells you which processing time we are talking about

Then:

• er = verb
• lang = adjective describing the subject

So the structure is:

[Subject] + [Verb] + [Adjective]

Yes, that is grammatical.

But there is a small difference in focus:

• Saksbehandlingstiden i bostedskommunen er lang
  This treats i bostedskommunen as part of the noun phrase and identifies which processing time you mean.

• Saksbehandlingstiden er lang i bostedskommunen
  This sounds a bit more like in the municipality of residence is extra information added at the end.

The original version is especially natural in formal written Norwegian.

Yes, that is possible.

• bostedskommunens saksbehandlingstid = the municipality of residence's processing time

That version is grammatical and quite formal. However, Norwegian often prefers an of/in-type structure with i or another preposition instead of stacking long nouns and genitives.

So:

• Saksbehandlingstiden i bostedskommunen er lang
  often sounds a bit easier and more natural than
• Bostedskommunens saksbehandlingstid er lang

especially in administrative writing.

Yes. It sounds quite formal and bureaucratic, which is very common in official texts.

Things that make it sound formal include:

• long compound nouns such as saksbehandlingstid
• administrative vocabulary such as bostedskommune
• a very compact sentence structure

In everyday speech, people might say something simpler, for example:

• Det tar lang tid å behandle saken i kommunen du bor i.

But the original sentence is perfectly natural in official or written contexts.