Learning the basics of Mandarin is very helpful. Most taxi drivers and shop clerks don’t speak a word of English. You can get by with just English in cities like Beijing and Shanghai, but your life will be limited: you’ll need to have addresses written out in characters before you set off and likely end up eating in expensive expat-oriented restaurants—or at McDonald’s.
Street signs are written in Chinese and pinyin (a Romanized version of Chinese), but shop signs are usually only in Chinese. The distinct system for naming roads and bridges takes some getting used to, and it can be hard to find an accurate map, says Ryan Phillips, an American who visited Shanghai on a librarian exchange, because construction happens at such a fast pace that resources quickly became outdated.
Even if you can only say a few words, the Chinese people you meet will appreciate your attempts to overcome the language barrier.