At the start of the movie when Iqbal practices bowling in the field, he closes his eyes and imagines a crowds roar as if in a stadium. He can never imagine this since he has never heard it. He clearly doesn't know what a crowds roar is like and can never have even the faintest idea about it since he is deaf and dumb since birth.
When Iqbal's sister is telling him what the cricket coach is telling his student, Girish Karnad says "okay kal milenge" which means we'll meet tomorrow. But his sister tells him "Aaj key liye itna hi" which means this is all for today. This is should not be the case since she is hearing Girish Karnad and translating his exact words.