Learn Turkish: Tedaviyi geciktirmekle sağlığını ihmal ediyorsun. - By delaying the treatment, you are neglecting your health.

This uses the grammar structure from your current lesson. We take the full infinitive verb geciktirmek (to delay) and add the instrumental suffix -le (a shortened form of ile, meaning "with" or "by"). This -mAk + -(y)lA structure tells us the method or means of doing something, which we usually translate to English as "by [doing an action]".

Why does tedaviyi take the accusative case here?

Even though geciktirmekle acts like an adverbial phrase in the main sentence, its root is still a verb that can take its own direct object. Because you are delaying a specific thing ("the treatment"), tedavi takes the accusative suffix -yi.

What is the root of the verb geciktirmek?

It actually comes from the word geç (late). From that root, we get the verb gecikmek (to be late or to be delayed). By adding the causative suffix -tir, the meaning changes to geciktirmek (to cause to be late, or to delay something).

Can you break down the suffixes on sağlığını?