East China is the new economic center of the country.
As anywhere in China, Mandarin is the lingua franca; nearly everyone can speak it. As elsewhere in China, English is not widespread but some people speak it quite well.
The region does have its own language, called Wu or Shanghainese. This is a populous region and the number of Wu native speakers is large; at 78 million it is rather more than French or Italian. There are local variants of Wu; the standard is that of Suzhou (an older city, capital of the Kingdom of Wu centuries back, and home to many scholars), not that of Shanghai.
Perhaps the commonest way to reach the area is to fly to Shanghai. There are two airports. Pudong is a major international airport with connections all over the world; Hong Qiao handles mainly domestic flights.
The area is also well connected via China's road and rail networks, and there is a Suzhou-Japan ferry.