Add 1 more, he united the Unit of weight measurement (very important at those times).During Qin Shi Huang period I dun thinK he make ppl speak chinese language. He did unite the writings of the 7 states into a uniform writing characters.
He did start the building of great wall......but the present great wall dun think any part is from Qin dynasty. Mostly if not all.......are from Ming Dynasty period.
His other major contributions I can think is 1. Unite the Roads (by making the axle of the carriage the same) 2. Unite the currency