Det var længe siden.

Word by word:

• det = it
• var = was
• længe = for a long time / long
• siden = since / ago

But the full sentence should be understood as an idiomatic whole, not just word-for-word. Depending on context, it can mean things like:

• It had been a long time
• It was a long time ago
• It had been ages

In Danish, det is often used as a kind of dummy subject, just like English it in sentences such as It is raining or It is late.

In Det var længe siden, det does not refer to a specific thing. It is there because Danish usually wants a subject in the sentence.

So here det is grammatical, not strongly meaningful by itself.

Var is the past tense of være (to be), so Det var længe siden places the situation in the past.

Compare:

• Det er længe siden = It has been a long time / It’s been a long time
• Det var længe siden = It had been a long time / It was a long time ago, depending on context

English often uses present perfect where Danish uses present:

• Det er længe siden literally looks like It is long since, but natural English is usually It’s been a long time.

Because længe is an adverb, while lang is an adjective.

• lang describes a noun: en lang dag = a long day
• længe describes duration or time: Jeg ventede længe = I waited a long time

In Det var længe siden, Danish needs the adverb længe, because it is talking about how much time had passed.

Here siden is part of the expression længe siden, which refers to time that has passed since something happened.

It often corresponds to English:

• ago
• since
• or part of it has been a long time since...

Examples:

• Det er længe siden = It’s been a long time
• Det er længe siden, jeg så ham = It’s been a long time since I saw him

So siden does not always translate neatly by itself. Its meaning depends a lot on the whole phrase.

Yes, very much so. Længe siden is a very common Danish expression for talking about a long time having passed.

You will often see it in patterns like:

• Det er længe siden = It’s been a long time
• Det var længe siden = It had been a long time
• Det er længe siden, at... = It’s been a long time since...

So it is best to learn længe siden as a chunk, not only as two separate words.

It can definitely stand alone, especially when the context already makes clear since when or since what.

For example, if two people meet again after many years, one might say:

• Det var længe siden.

In a fuller sentence, Danish often adds a clause:

• Det var længe siden, vi havde set hinanden. = It had been a long time since we had seen each other.

So the short version is completely natural when the rest is understood.

The main difference is tense.

• Det er længe siden is used from the speaker’s current point of view.
  • It’s been a long time
• Det var længe siden is used from a past point of view.
  • It had been a long time
  • sometimes It was a long time ago, depending on context

Example:

• Nu ser jeg ham ofte, men dengang var det længe siden, vi havde talt sammen. = Now I see him often, but back then it had been a long time since we had spoken.

Because Danish expresses this idea differently. English often says:

• for a long time
• it has been a long time since...

Danish uses the idiom længe siden instead of building the phrase the same way as English.

So even though an English speaker may expect something like for, Danish simply does not need it here.

The basic word order is:

• Det = subject
• var = verb
• længe siden = time expression

So the pattern is very straightforward: subject + verb + adverbial expression

In main clauses, Danish normally keeps the finite verb in second position, and this sentence follows that rule.

A careful pronunciation is roughly:

• det = something like de
• var = something like va
• længe = roughly LEN-uh with a Danish æ
• siden = roughly SEE-then or SEE-den, depending on accent and reduction

In natural speech, Danish often reduces sounds, so it may come out more smoothly and less clearly separated than the spelling suggests.

A rough learner-friendly version: de va leng-e see-then

But it is best to listen to native audio, especially for æ, the soft d, and the rhythm.

Yes. Very often it does.

Depending on context, Det var længe siden can sound:

• nostalgic
• surprised
• friendly
• slightly dramatic, like Wow, it’s been ages

For example, if you meet an old friend, saying Det var længe siden can feel very natural and warm.

So although the grammar is simple, the expression is common in real conversation and can carry a lot of feeling.