Learn Turkish: Toplumun benimsediği çeşitliliği garipsemiyordu. - He didn't use to find the diversity adopted by society strange.

The suffix -(I)msEmEk (which often shortens to just -sEmEk depending on the root) attaches to nouns or adjectives to mean "to perceive as X" or "to feel that something is X". Here, it attaches to garip (strange) to make garipsemek (to find strange). The rest of the word is the negative -me (narrowed to -mi before -yor), present continuous -yor, and past -du, giving us "didn't use to find strange".

I notice benimsediği looks like it might have the same suffix. Is it related?

Exactly! It is built from benim (mine) plus the same attitude suffix -se, creating benimsemek. Literally, it means "to perceive as mine," which is how Turkish expresses "to adopt," "to embrace," or "to internalize" a concept or practice.

Why is society written as Toplumun (with the genitive case) instead of just Toplum?

This is a great refresher for relative clauses. Because toplum is the subject of the action in the phrase "the diversity that society adopted", it must take the genitive case (Toplumun). The verb then takes the -dik object participle plus a possessive suffix matching the subject (benimsediği).

Let's break down çeşitliliği. Why did the change to , and what is the final ?