The official language of the People’s Republic of China is called Putonghua, which translates directly as ‘common speech’, but which is generally known in the Western World as Mandarin Chinese. However, Chinese government figures suggest that only around 53 per cent of the population actually speak Putonghua. This is of course not as depressing a figure as it might sound - 53 per cent of people in China still represents the vast majority of people anyone is likely to meet while there, and so an understanding of Putonghua is likely to see any visitor making themselves at least relatively well understood.
Certainly this is the largest single proportion of people to understand a single language in the country, and so represents the ‘best bet’ if visiting China. Perhaps the most curious feature of the Chinese languages though is what happens when you write them down. There are different dialects prevalent in, say Beijing and Guangzhou (where Cantonese is widely used), and so the pronunciation of words will be entirely different in the two places. But if you write the word down, it will be exactly the same in both places, because the Chinese dialects do not apply to the written form. So while the spoken word ‘dog’ is utterly different across the country, the written word ‘dog’ will be understood nationwide.
This added to the fact that as a spoken language there are relatively few words, and the fact that most words can have up to four different meanings depending on inflection and tone, is why most TV programmes in China have subtitles.