The text bug happened with Ismail. The first and second thing he said both appeared at the same time in his speech bubble.
I played again and the text bug didn't happen that time... but when I chose the murderer at the end, nothing happened. The screen was just stuck in the office with the message about no one knowing Ahmet lived in the neighbourhood.
I used Firefox both times.
Good luck with it! Like I said, it's a great concept for a short language learning game.