This is the 5678th most frequent Turkish word.
projelerini
"Projelerini" means "their projects" or "his/her/its projects" depending on context.
In this example, 'projelerini' is used to denote 'his projects' to signify the items being completed before the action of giving a presentation.
Projelerini tamamladıktan sonra bir sunum yapacak.
He will give a presentation after completing his projects.
In this sentence, 'projelerini' is used with the third-person singular possessive suffix and the accusative case to indicate 'his projects' as the object of the verb 'explained'.
Ahmet projelerini sunumda detaylı bir şekilde anlattı.
Ahmet explained his projects in detail during the presentation.
Here, 'projelerini' is again possessive and accusative, indicating 'his projects' as the entity being improved or worked on.