Learn Turkish: Denizciler rüzgâr yelkenleri şişirsin diye bekliyor. - The sailors are waiting so that the wind fills the sails.

In Turkish, purpose clauses with diye ("so that" or "in order to") often use the imperative or optative mood. You can think of it as quoting the subject's internal intention or wish. The sailors are waiting, and their thought is literally: "Let the wind fill the sails!"

This lesson is about using -mAsIyla to connect events. Why can't we say rüzgârın yelkenleri şişirmesiyle bekliyor?

The -mAsIyla structure (verbal noun + ile) describes an event that triggers another event, meaning "upon X happening" or "because X happened". But here, the wind hasn't filled the sails yet! The sailors are waiting for it to happen. To express a future goal or purpose ("so that"), we must use diye or için, not -mAsIyla.

Could we use a verbal noun with için here instead of diye?

Yes! You could also say rüzgârın yelkenleri şişirmesi için bekliyor. In that case, rüzgâr takes the genitive suffix (-ın) because it becomes the owner of the verbal noun şişirmesi. The diye structure is often preferred in daily speech because it lets you use a plain, independent sentence (rüzgâr yelkenleri şişirsin) without worrying about genitive and possessive suffixes.

Why is the accusative suffix -i used on yelkenleri?