China has many regional languages (or dialects) like Cantonese, Mongolian, Uighur, Hakka, Tibetan, but when you say Chinese language, it usually means Chinese Mandarin (aka Putonghua) which is the official language of China, most of Chinese people are able to understand this language, when I say "most of" that means some older people (age of 60+) can't understand, but for younger generation, almost 100% of them can understand and speak it.
Compare to India, I think China still has less people can speak English for the history reason, but yes, this is changing now, as you may know, English is already a compulsory subject from the elementary school.
