Learn Turkish: Toplantıyı ertelemekle hiçbir sorunu önlemiyoruz. - By postponing the meeting, we are not preventing any problem.

It combines the infinitive ertelemek (to postpone) with the suffix -le (a shortened form of ile, meaning "with" or "by"). In Turkish, attaching ile or -(y)lA to a -mAk infinitive creates a structure that translates to "by doing" an action.

Why does toplantı take the accusative suffix -yı in this sentence?

Even though ertelemekle acts like an adverb here, it is still built from a transitive verb and can take its own direct object. Because we are referring to a specific meeting ("the meeting"), toplantı gets the definite accusative suffix.

There are two words with accusative endings (toplantıyı and sorunu). How do we know which verb they belong to?

In Turkish, objects usually come right before the verb or verbal word they belong to. Toplantıyı (the meeting) is the direct object of the verbal noun ertelemekle (by postponing), and hiçbir sorunu (any problem) is the direct object of the main verb önlemiyoruz (we are not preventing).

Why is the main verb önlemiyoruz negative if hiçbir already means "no" or "none"?

Turkish requires negative matching. Whenever you use a negative word like hiçbir (no / not any), the verb must also be negative. Literally, this says "we are not preventing no problem", which translates to English as "we are not preventing any problem".