Learn Turkish: Senaryoyu ezberlemeyenler bu rolü oynayamaz. - Those who do not memorize the script cannot play this role.

It uses the subject relative clause suffix -en. The root is ezberlemek (to memorize). We add the negative suffix -me, a buffer -y-, and then -en to make ezberlemeyen (the one who does not memorize). Because there is no noun after it (like "actors" or "people"), we add the plural suffix -ler directly to the verb to mean "those who do not memorize".

Why is senaryo in the accusative case (senaryoyu) if it's not the main verb's object?

Participles like ezberlemeyen still act like verbs, so they take their own objects. Since "the script" is the specific thing being memorized, it takes the accusative case suffix -yu (with the buffer -y-).

Why does rol take the -ü suffix for the accusative (rolü) instead of -u?

Usually, after an "o", vowel harmony rules say we should use -u. However, rol is a foreign loanword. These types of loanwords often break vowel harmony rules, taking front vowels like -ü instead. Other common examples you might remember are saat becoming saati or kalp becoming kalbi.

What makes oynayamaz mean "cannot play" rather than just "does not play"?