Hengslet sitter på hengselplaten.

Because hengslet is a definite form: the hinge.

The basic dictionary form is et hengsel = a hinge.
In the definite singular, Bokmål can use hengslet, and you may also see hengselet. This happens with some nouns ending in -el, where the unstressed e may disappear in inflected forms.

So:

• et hengsel = a hinge
• hengslet / hengselet = the hinge

Because hengselplaten is also in the definite singular: the hinge plate.

The main noun in the compound is plate, which is a common-gender noun:

• en plate = a plate
• platen = the plate

When it becomes a compound, the definite ending still goes on the last part:

• en hengselplate = a hinge plate
• hengselplaten = the hinge plate

Because Norwegian normally writes compound nouns as one word.

So where English often writes:

• hinge plate

Norwegian usually writes:

• hengselplate

This is very common in Norwegian. The last part is the main noun, and the first part describes it.

In Norwegian, sitte is often used not only for people who are sitting, but also for things that are positioned, attached, or fixed somewhere.

So Hengslet sitter på hengselplaten suggests that the hinge is mounted/placed/attached on the hinge plate, not just that it exists there.

If you said er, the sentence would still be understandable, but sitter sounds more natural when talking about how an object is physically set in place.

Not in a fully literal English sense.

It is the same verb as to sit, but Norwegian uses it much more broadly than English does. For objects, it can mean things like:

• is sitting
• is positioned
• is mounted
• is attached
• is located

So here, sitter is best understood as something like is attached/is positioned.

På often means on, but in Norwegian it can also cover meanings like on, onto, at, or attached to, depending on context.

In this sentence, på hengselplaten means that the hinge is physically on or attached to the hinge plate.

So på is the natural choice because there is surface contact or mounting.

Because Norwegian usually expresses the by adding an ending to the noun.

In this sentence:

• hengslet = the hinge
• hengselplaten = the hinge plate

This is one of the biggest differences from English. Instead of a separate article before the noun, Norwegian often uses a suffix.

A separate word such as den/det is usually added only in certain cases, especially with adjectives:

• den store platen = the big plate

The dictionary forms are:

• et hengsel = a hinge
• å sitte = to sit / to be situated
• en hengselplate = a hinge plate

That means the sentence is built from very normal base forms plus definite endings and a present-tense verb.

No. This is a very basic Norwegian main clause:

• Hengslet = subject
• sitter = verb
• på hengselplaten = prepositional phrase

So the structure is:

• Subject + verb + place

That is completely normal.

Yes, it would be understandable, but it is usually less natural in this kind of technical or physical description.

• er simply says the hinge is there
• sitter suggests it is set, mounted, or attached there

So sitter gives a more precise and idiomatic description of how the hinge is positioned.

Because the sentence is talking about a specific hinge and a specific hinge plate, not just any hinge and any plate.

So:

• hengslet = the hinge
• hengselplaten = the hinge plate

If you wanted a more general or indefinite meaning, you could use indefinite forms instead:

• Et hengsel sitter på en hengselplate.

That would mean A hinge is attached to a hinge plate, which sounds more general or like a description of a type of setup.