Diyelim ki otobüsü kaçırdık; ne yapacağız?

Yes. Diyelim ki is a very common expression meaning let’s say, suppose, or imagine that.

It is often used to introduce a hypothetical situation:

• Diyelim ki yağmur başladı. — Suppose it started raining.
• Diyelim ki geç kaldık. — Let’s say we were late.

So in your sentence, Diyelim ki otobüsü kaçırdık sets up a scenario: Suppose we missed the bus.

Yes. Diyelim comes from the verb demek (to say).

Here, diyelim literally means something like let us say. That is why it works so naturally as let’s say / suppose.

So:

• demek — to say
• diyelim — let’s say

Even though it literally contains let’s say, in real usage it often just means suppose.

Here, ki links the expression diyelim to the clause that follows. It is similar to that in English, though in natural English we often do not translate it directly.

So:

• Diyelim ki... — Suppose that... / Let’s say...

In modern Turkish, ki is very common after expressions like this. It helps mark that a full clause is coming next.

Because otobüsü is the definite direct object form.

The verb kaçırmak here means to miss something, as in to miss the bus. When the object is specific or definite, Turkish usually uses the accusative ending.

• otobüs — bus
• otobüsü — the bus / a specific bus, as the direct object

So:

• otobüsü kaçırdık — we missed the bus

If you said otobüs kaçırdık, it would sound unnatural here.

It is built from:

• otobüs — bus
• -ü — accusative ending

So:

• otobüs + ü = otobüsü

The final vowel is ü because of vowel harmony.

Also, the word already ends in s, so there is no extra buffer consonant needed here. The form is simply otobüsü.

Kaçırdık means we missed.

It comes from:

• kaçırmak — to miss; to let slip; to fail to catch
• kaçırdı- — missed
• -k — we

More specifically:

• kaçır- — verb stem
• -dı/-di/-du/-dü — past tense
• -k — first person plural

So:

• kaçırdık — we missed

In this sentence, it means we missed the bus.

This is very natural in Turkish.

The first clause gives the hypothetical situation:

• Diyelim ki otobüsü kaçırdık — Suppose we missed the bus

Then the second clause asks about the result or response:

• ne yapacağız? — what will we do?

So the idea is:

• Suppose we missed the bus; what will we do?

English does the same kind of tense shift:

• past in the hypothetical setup
• future for the next action

Yes, definitely.

A very common alternative is:

• Otobüsü kaçırırsak ne yapacağız?
• If we miss the bus, what will we do?

The difference is mainly in style and framing:

• Diyelim ki otobüsü kaçırdık... = Let’s say / suppose we missed the bus...
• Otobüsü kaçırırsak... = If we miss the bus...

The version with diyelim ki feels more like introducing a scenario for discussion.

Both can be possible in Turkish, but they give slightly different feelings.

• Ne yapacağız? — What will we do?

  • sounds like a concrete future situation
  • often used when thinking about the next step

• Ne yaparız? — What do we do? / What would we do?

  • can sound more general, habitual, or less immediate

In your sentence, ne yapacağız? fits well because the speaker is thinking about a specific possible situation and the action that would follow.

Here it is hypothetical, not a statement about something that really happened.

Even though kaçırdık is a past form, with diyelim ki it is used to create an imagined scenario:

• Suppose we missed the bus

So the sentence is not saying we actually missed it. It is saying imagine that we did.

Yes, Turkish word order is flexible, though some versions sound more natural than others.

The given sentence is very natural:

• Diyelim ki otobüsü kaçırdık; ne yapacağız?

You may also hear:

• Otobüsü kaçırdık diyelim, ne yapacağız?

That also works, but it has a slightly different rhythm and emphasis.

For learners, the original order is a very good pattern to remember:

• Diyelim ki + clause

The semicolon separates two closely connected parts:

1. Diyelim ki otobüsü kaçırdık
2. ne yapacağız?

It shows a stronger break than a comma, but the ideas still belong together.

In everyday writing, you might also see:

• Diyelim ki otobüsü kaçırdık, ne yapacağız?

And in speech, the punctuation is not important; what matters is the pause and intonation.

It is generally neutral and very common. You can use it in everyday conversation, teaching, explanations, and writing.

It is not especially formal, and it is not slang. That makes it a very useful expression for learners.

No. Kaçırmak has several related meanings depending on context.

Common meanings include:

• to miss
  
  • otobüsü kaçırmak — to miss the bus
• to let something escape / lose the chance for something
• sometimes to kidnap / abduct in other contexts

So context matters a lot. In your sentence, because the object is otobüsü, the meaning is clearly to miss the bus.