Learn Hardcore Norwegian: Mobilbruk er ikke tillatt i forelesningssalen. - Mobile phone use is not allowed in the lecture hall.

Mobilbruk is a compound noun: mobil (mobile phone) + bruk (use). In Norwegian, compound nouns are almost always written as one word, not as two separate words.

✅ Correct: mobilbruk
❌ Wrong: mobil bruk (looks like “mobile use” in the sense “mobile, moving use”)

If you want to separate the words, you’d normally use a preposition:

bruk av mobil = use of a mobile (more literal, a bit more formal/written)

But mobilbruk is the most natural, compact way to say “mobile phone use” in this kind of notice.

What exactly is mobilbruk grammatically? Is it singular or plural, and what gender is it?

Mobilbruk is:

a singular noun
a mass/uncountable noun (like “smoking”, “alcohol consumption”)
most naturally treated as masculine (though you almost never need to show its gender here)

In this sentence it is used in the bare singular, indefinite form to talk about mobile phone use in general:

Mobilbruk er ikke tillatt … = Mobile phone use (in general) is not allowed …

Why is there no article in front of mobilbruk? Why not Den mobilbruken er ikke tillatt?

When Norwegian talks about something in general, especially an activity or mass noun, it often uses the bare singular without any article:

Røyking er forbudt. = Smoking is prohibited.
Alkoholbruk er ikke tillatt. = Alcohol use is not allowed.
Mobilbruk er ikke tillatt. = Mobile phone use is not allowed.

If you said:

Den mobilbruken er ikke tillatt,

it would sound like you’re referring to some specific type or instance of mobile use that was mentioned earlier. For a general rule on a sign, no article is correct.

What does tillatt mean exactly, and what kind of word is it?

Tillatt is the past participle of the verb tillate (“to allow, to permit”), and here it functions as an adjective meaning “allowed / permitted”.

å tillate = to allow
(noe) er tillatt = (something) is allowed

So:

Mobilbruk er ikke tillatt
literally: “Mobile (phone) use is not allowed.”

Is there a difference between ikke tillatt and forbudt?

Yes, there’s a nuance:

ikke tillatt = “not allowed / not permitted.”
Slightly more neutral, formal, often used in rules, regulations, and official notices.
forbudt = “forbidden / prohibited.”
Sounds a bit stronger and more absolute.

Both could be used in this context, but:

Mobilbruk er ikke tillatt i forelesningssalen.
Mobilbruk er forbudt i forelesningssalen.

The first sounds more like “This is against the rules,” the second a bit more like “This is strictly forbidden.”

Why is the word order er ikke tillatt and not er tillatt ikke?

Norwegian normally places ikke (not) after the finite verb in a simple main clause:

Mobilbruk er ikke tillatt.
(verb er, then ikke)

Putting ikke after the adjective would be wrong or at least very unnatural:

❌ Mobilbruk er tillatt ikke.

Compare:

Han er ikke hjemme. = He is not home.
Det er ikke mulig. = It is not possible.

So [verb] + ikke + [rest of the predicate] is the standard pattern here.

How is forelesningssalen built up, and what does it literally mean?

Forelesningssalen is another compound:

forelesning = lecture
sal = hall (a large room)
forelesningssal = lecture hall
forelesningssal
- -en (definite suffix) → forelesningssalen = the lecture hall

So literally:

i forelesningssalen = “in the lecture hall”

Why is it forelesningssalen (definite form) and not en forelesningssal or just forelesningssal?

Using the definite form points to a specific, known lecture hall, usually the one both speaker and listener have in mind (e.g., the hall at this university/building).

i forelesningssalen = in the lecture hall (the specific one)
i en forelesningssal = in a lecture hall (any such room; more vague)

For posted rules and signs in a building, you normally use the definite:

Røyking er forbudt i bygningen. = Smoking is prohibited in the building.
Mobilbruk er ikke tillatt i forelesningssalen. = Mobile use is not allowed in the lecture hall (here).

Why is the preposition i used? Could you also say på forelesningssalen?

Here i means “in, inside”, which fits a room:

i forelesningssalen = in the lecture hall (inside the room)

You would not say på forelesningssalen in this meaning.

However, you can say:

på forelesningen = at the lecture / during the lecture

So:

Mobilbruk er ikke tillatt i forelesningssalen.
= inside the room

vs.

Mobilbruk er ikke tillatt på forelesningen.
= during the lecture (as an event)

How could I say this in a more everyday or more natural spoken way?

Two very common alternatives in speech and on signs are:

Det er ikke lov å bruke mobil i forelesningssalen.
= Literally “It is not allowed to use (a) mobile in the lecture hall.”
Det er ikke lov med mobilbruk i forelesningssalen.
= Literally “It is not allowed with mobile use in the lecture hall.”

ikke lov is slightly more informal and very frequent in everyday Norwegian.

Could I also say Mobiler er ikke tillatt i forelesningssalen?

You could, but it sounds a bit odd and less natural.

Mobiler er ikke tillatt … focuses on the objects (phones) themselves, like “Phones are not allowed …”

Norwegians usually prefer to talk about the use of phones:

Mobilbruk er ikke tillatt … (most natural)
Det er ikke lov å bruke mobil i forelesningssalen. (very common)

So it’s better to copy the “use” formulation rather than plural “mobiler”.

How would I turn this into a yes/no question in Norwegian?

For a yes/no question, you move the verb er to the front:

Er mobilbruk tillatt i forelesningssalen?
= Is mobile phone use allowed in the lecture hall?

Notice that ikke disappears when you ask whether it is allowed; you only add it if you want to ask whether it is not allowed:

Er mobilbruk ikke tillatt i forelesningssalen?
(grammatically correct, but sounds a bit marked/surprised: “Is mobile use not allowed in the lecture hall?”)