How does indefinite accusative work? Does 'Bir balik yer' mean 'he/she/it eats a fish'or 'a fish eats' and how can you tell?
If the word ends in a consonant you don't have to add the 'y'. And if it ends in 'k' it becomes 'ğ'.
The same happens for:
't' which becomes 'd'
'p' - 'b'
'ç' - 'c'
You can find more about this on the tips and notes section of Accusative. https://www.duolingo.com/skill/tr/Accusative