Learn Turkish: Dün 'Rüzgâr' diye bir şarkıcı dinledik, sesi çok amatördü. - Yesterday we listened to a singer called 'Rüzgâr', his voice was very amateur.

You have likely seen diye used for reported speech or to mean 'because'. Here, it functions as a naming label. The pattern [Name] diye bir [Noun] is the standard way to say 'a [Noun] called [Name]' in Turkish. So, 'Rüzgâr' diye bir şarkıcı translates perfectly to 'a singer called Rüzgâr'.

We listened to the singer. Why does şarkıcı lack an accusative ending like şarkıcıyı?

The verb dinlemek (to listen) takes the accusative case only when the object is specific. Because we are introducing a new, unspecific person using bir (a singer), the noun remains in the plain nominative case without a case marker.

Why is the word for voice written as sesi instead of just ses?

The -i at the end of sesi is the third-person possessive suffix, meaning 'his' or 'her'. While in English we might just say 'the voice was very amateur', Turkish prefers to link the attribute directly to its owner, making it literally 'his voice'.

Why does the past tense suffix on amatör take the form -dü rather than -du?