Learn Turkish: İnsan yaşlanmayı kabullenirse, daha huzurlu olur. - If a person accepts aging, they will be more peaceful.

Both mean 'to accept,' but kabul etmek is usually used for accepting a concrete offer, invitation, or a simple fact. Kabullenmek implies a deeper psychological process: coming to terms with something difficult and internalizing it. Because aging is a personal, emotional process, kabullenmek is the perfect fit.

'Aging' is a general concept here. Why does yaşlanmayı take the specific accusative suffix?

Even when talking about abstract or general concepts, the verb kabullenmek strongly prefers its direct object to be marked with the accusative case. The verbal noun yaşlanma (aging) takes the buffer letter y and the accusative suffix ı to satisfy this rule.

Why are both verbs conjugated using the aorist tense (kabullenirse, olur)?

Using the aorist in both the condition (-ir-se) and the result (-ur) is the standard way to express a timeless, universal truth in Turkish. It works like the zero conditional in English, showing that this rule about human nature applies generally at all times.

Why is the singular word İnsan translated as 'a person' or 'they' instead of 'the human'?

In Turkish, using the singular insan without any adjectives or determiners is the standard way to make generalizations about humanity. It functions exactly like the generic 'one', 'you', or 'they' in English when stating universal facts.