Learn Hardcore Norwegian: Diskusjonen på møtet var lang, men alle deltakerne var høflige. - The discussion at the meeting was long, but all the participants were polite.

You do not normally say den diskusjon or det møte in this kind of sentence; you use the suffixed definite form instead: diskusjonen, møtet.

Why is the preposition på used in på møtet and not i møtet or something else?

På is the most common preposition with events, meetings, parties, etc.:

på møtet = at the meeting
på festen = at the party
på kurset = at the course

You can sometimes see:

i møtet – more literally “in the meeting”, often used when you mean in this particular session/agenda item, or in formal/administrative language.
under møtet – “during the meeting”, focusing on the time span rather than the location or event.

In this sentence, på møtet is the natural, neutral way to say “at the meeting.”

Why is it var lang and not var lenge?

Lang is an adjective = “long” (describing a thing).
Lenge is an adverb = “for a long time” (describing how long something lasts).

Diskusjonen var lang.
The discussion was long. (Long discussion.)
Diskusjonen varte lenge.
The discussion lasted for a long time.

Because diskusjonen is a noun being described, you use the adjective lang, not the adverb lenge.

What exactly does deltakerne mean, and how is it formed?

The base noun is:

en deltaker = a participant

Then:

deltakere = participants (indefinite plural)
deltakerne = the participants (definite plural)

So alle deltakerne = all the participants.

The ending -ne marks definite plural here. A very common pattern is:

singular indefinite: - (no ending)
plural indefinite: -er
plural definite: -ene or -ne (here: -ne)

Why is the adjective høflige (with -e) and not høflig?

Predicative adjectives (adjectives that come after er/var/blir, etc.) agree in number with the subject:

Singular: hun er høflig – she is polite
Plural: de er høflige – they are polite

Here, the subject is alle deltakerne (all the participants) = plural, so you use the plural form høflige.

So:

Alle deltakerne var høflige.
All the participants were polite.

Could you also say Alle var høflige instead of Alle deltakerne var høflige?

Yes, grammatically that’s fine:

Alle var høflige. – Everyone was polite.

The difference is in how specific you are:

Alle deltakerne var høflige.
Emphasizes that all of the participants (as a defined group) were polite.
Alle var høflige.
Relies more on context for who “everyone” is. It’s less explicit that you mean the participants at the meeting, though that would usually be understood from context.

What role does alle play in alle deltakerne? Why not deltakerne alle?

Alle is a quantifier meaning all.

In Norwegian, alle normally comes before the noun (or noun phrase):

alle deltakerne = all the participants
alle barna = all the children
alle disse bøkene = all these books

Deltakerne alle is not natural Norwegian in this meaning. The normal word order is:

alle + [definite plural noun] → alle deltakerne

Why is there a comma before men?

Norwegian almost always uses a comma before men when it links two full clauses:

… var lang, men alle deltakerne var høflige.

Each side has its own subject and verb:

Diskusjonen på møtet var lang
alle deltakerne var høflige

So you write a comma before men to separate the clauses, similar to English:

… was long, but all the participants were polite.

Could I say langvarig instead of lang, and what would be the difference?

You could say:

Diskusjonen på møtet var langvarig.

Lang = long (in length or duration, very general).
Langvarig = long-lasting, prolonged, often slightly more formal or emphasizing that it went on for quite a while.

In everyday speech, lang is more common and neutral. Langvarig can sound a bit more formal or evaluative, like “protracted” or “lengthy” in English.