Question on Hemispheric Lateralisation

Robert suffered a stroke at the age of 55. After the stroke he was paralysed down his right side, though he could move his left arm and leg easily. Robert could clearly understand what was said to him, but was unable to produce any speech.
Discuss how knowledge of hemispheric lateralisation and language centres in the brain has helped our understanding of cases such as Robert’s. Refer to Robert’s case in your answer.

16 marks.