Questions & Answers about Gölgeyi gördükten sonra bir çığlık duydum.
How does gördükten sonra mean "after I saw"?
To say "after doing an action" in Turkish, you take the verb root and add -dıktan (or -dikten, -duktan, -dükten) followed by sonra. Here, gör- (to see) becomes gördükten sonra (after seeing). Notice that there is no personal "I" ending on this word; we understand it means "after I saw" because the main verb at the end of the sentence is duydum (I heard).
Since we are learning about the ki conjunction, could I use ki instead of sonra here?
You can, but it changes the feeling! While this sentence uses -dıktan sonra to state a simple timeline ("After I saw..."), you could use the realization/consequence ki to add drama. If you said Gölgeyi gördüm ki bir çığlık duydum, it means "I saw the shadow, and then suddenly I heard a scream!" Using ki gives a strong sense of surprise or immediate consequence.
Why does gölge (shadow) have the -(y)i ending?
It has the accusative case ending because it is the specific direct object being seen. By adding the buffer y and the vowel i, gölge (shadow) becomes gölgeyi (the shadow).
If gölgeyi takes the accusative ending, why doesn't (a scream) have one?