Learn Turkish: Diyelim ki çok paran var, ne alırsın? - Suppose you have a lot of money

The root is de- (to say). When we add the "let's" suffix -elim, we need the buffer consonant -y-. In Turkish, the y sound often narrows a preceding e or a into an i or ı. Because of this vowel narrowing, de-y-elim becomes diyelim (let's say).

Does diyelim ki work just like "suppose that" in English?

Yes! Diyelim means "let's say," and the conjunction ki acts like "that." Together, diyelim ki is used exactly like "suppose that" to introduce a hypothetical scenario. Notice how it lets you keep the rest of the thought in a normal statement format (çok paran var) instead of forcing you to use conditional suffixes like -sa.

The English translation says "what would you buy", but alırsın is in the present aorist tense. Why not use a conditional tense?

In Turkish, the aorist (broad) tense is the go-to form for hypothetical future actions or potential choices. While English uses "would" here, Turkish treats a "suppose that..." scenario as a newly established reality. The aorist (alırsın) perfectly captures the "what is your natural choice in that situation?" feeling, whereas a past aorist like alırdın would sound more like "what would you have bought?" in a past unreal scenario.

How does this relate to the -mIş gibi (as if) structure we are currently learning?