Learn Turkish: Bacakları güçsüzleşirse dedem ister istemez baston kullanır. - If his legs become weak, my grandfather inevitably uses a cane.

İster istemez is a frozen phrase formed using the aorist tense of istemek (to want) in both its positive (ister) and negative (istemez) forms. It literally means "whether he wants to or not." In this sentence, it functions as an adverb meaning the action will happen regardless of his preference, which naturally translates to "inevitably."

Could I place ister istemez at the very end of the sentence?

It is much better to keep it right before the verb or the object of the verb. In Turkish, adverbs generally sit close to the verbs they modify. Placing it between the subject (dedem) and the object phrase (baston kullanır) sounds the most natural.

How is the verb güçsüzleşirse built from the root word for "strength"?

It starts with the noun güç (strength). We add -süz (without) to make the adjective güçsüz (weak). Then we add -leş (to become) to form the verb güçsüzleşmek (to become weak). Finally, it takes the aorist and conditional suffixes (-ir-se) to mean "if they become weak."

Why use the aorist tense for both güçsüzleşirse and kullanır?

The aorist (seen in the -ir and -ır suffixes) is used here because this sentence describes a general, hypothetical truth rather than a specific event happening right now. It implies "whenever his legs get weak, he habitually uses a cane."