Why did Yang Zhenning stay in the United States for so long, speak such poor English and have a terrible accent in China?

As an English-speaking person from China, even if your pronunciation is standard, you can't compare with the homeless people on the streets of the United States. It is normal to have an accent. There is no fixed standard for pronunciation. British people speak British English, Americans speak American English, Singaporeans speak Singapore English and Thais speak Thai. This is no problem. People in China speak Chinglish, which is one of the signs of a country's rise. No matter what Yang Zhenning's accent is, there is no such great physicist in the world. Even if Yang Zhenning teaches in Chinese in the United States and brings an interpreter, you must ask him to give a speech in the United States, because others don't have what Yang Zhenning thinks.