Learn Turkish: Çığlık sesi müziğe denk geldiğinde seyirci şaşırdı. - When the scream sound coincided with the music, the audience was surprised.

This is the exact structure your current lesson is teaching! It comes from the verb gelmek. We add the participle suffix -dik (which becomes -diğ due to consonant mutation), followed by the third-person possessive -i (referring to the event's coinciding), the buffer letter -n-, and the locative case -de (meaning at, in, or on). You can think of it literally as "at the time of its coming".

Why is müzik written as müziğe?

The verb phrase denk gelmek (to coincide or to happen to meet) requires the dative case (-e or -a) because something coincides to or with something else in Turkish. When we add the dative suffix -e to müzik, the final k softens to a ğ through consonant mutation, making it müziğe.

Why does ses have an -i at the end in çığlık sesi?

This is a classic noun compound, which you have likely seen in earlier lessons. In Turkish, when two nouns are put together to make a new specific concept (like scream and sound), the second noun must take a possessive suffix. So, çığlık (scream) plus ses (sound) plus the -i possessive suffix becomes çığlık sesi.

What does the phrase denk gelmek mean on its own?