Jeg gætter på, at bussen er forsinket igen.

In this sentence, at gætte på is the natural Danish expression for to guess / to suppose about something.

• Jeg gætter på, at ... = I guess / I’m guessing that ...

Without på, gætte often feels more like guessing an answer:

• Jeg gætter svaret = I guess the answer
• Jeg gætter på, at han kommer = I guess that he’s coming

So here, på is part of the expression.

At here means that. It introduces a subordinate clause:

• Jeg gætter på = I guess
• at bussen er forsinket igen = that the bus is delayed again

So the sentence is built like this:

• main clause: Jeg gætter på
• subordinate clause: at bussen er forsinket igen

In everyday Danish, at can sometimes be omitted in speech, but including it is very common and completely correct.

Bussen means the bus.

In Danish, the definite article is often added to the end of the noun:

• en bus = a bus
• bussen = the bus

This is one of the first big differences from English. Instead of putting the before the noun, Danish usually attaches it as an ending.

Because after at, Danish uses normal subordinate-clause word order.

So you get:

• at bussen er forsinket igen

This is different from a question, where you would say:

• Er bussen forsinket igen? = Is the bus delayed again?

So:

• statement/subordinate clause: bussen er
• question: er bussen

Forsinket means delayed / late.

It is the past participle of forsinke (to delay), but in this sentence it functions like an adjective after er:

• Bussen er forsinket = The bus is delayed

This is very similar to English:

• The bus is delayed

You can think of er forsinket as a fixed and very common way to say that transport is late.

Danish often expresses this idea with være + past participle:

• Toget er forsinket = The train is delayed
• Flyet er forsinket = The plane is delayed

You can also say something with sen in some contexts, but for buses, trains, flights, etc., forsinket is the standard and most natural word.

So bussen er forsinket is the most idiomatic wording here.

Igen means again.

It comes at the end because that is a very natural position in Danish for this kind of adverb:

• Bussen er forsinket igen = The bus is delayed again

You could move adverbs around in some cases for emphasis, but the final position is the most neutral and common here.

In standard Danish spelling, subordinate clauses are usually separated by a comma, so you write:

• Jeg gætter på, at bussen er forsinket igen.

That comma marks the start of the at-clause.

English punctuation is a bit different, so this may look unusual if you are coming from English.

Yes. That is also correct, but the nuance is a little different.

• Jeg gætter på, at ... = I guess / I’m guessing that ...
• Jeg tror, at ... = I think / I believe that ...

Gætter på can sound a little more like you are making a guess without much certainty. Tror can sound a bit more like your actual belief or opinion.

In many everyday situations, though, they can be quite close.

Because Danish main clauses normally follow the V2 pattern: the finite verb is in the second position.

Here the sentence starts with the subject:

• Jeg = first position
• gætter = second position

So the normal order is:

• Jeg gætter på, at ...

If you put another element first, the verb still stays in second position:

• I dag gætter jeg på, at bussen er forsinket igen.

That is a very important Danish word-order rule.

Yes. Gætter is the present tense of at gætte.

• at gætte = to guess
• jeg gætter = I guess / I am guessing

Danish present tense often covers both the simple present and the English progressive, depending on context.

So jeg gætter can correspond to:

• I guess
• I’m guessing

A rough learner-friendly guide is something like GYET-er, but the real Danish sounds are softer and less clear-cut than English ones.

A few pronunciation notes:

• gæ- has a vowel somewhat like the e in get, but it is not exactly the same.
• The tt does not sound strongly like English t-t.
• The final -er in Danish is often a weak, reduced sound.

Also, the d in forsinket is not pronounced like a strong English d. Danish pronunciation is often much softer than the spelling suggests.

Sometimes in informal speech, yes:

• Jeg gætter på bussen er forsinket igen.

But many learners should stick to the version with at, because it is clearer and fully standard:

• Jeg gætter på, at bussen er forsinket igen.

Using at helps you see the structure of the sentence more easily.

Yes, it is natural and common, especially in casual conversation.

It sounds conversational and everyday. Other common alternatives are:

• Jeg tror, at ... = I think that ...
• Jeg regner med, at ... = I expect / assume that ...
• Mon ikke ... = I’d imagine / probably ...

So Jeg gætter på, at bussen er forsinket igen is perfectly natural Danish.