Chinese characters represent ideas in a broad sense. They sometimes have a reference to a general sound embodied in them. There are many varieties of chinese, called dialects. They are so distinct that speakers of one dialect cannot understand the other, if the speaker has no knowledge of the sounds in the other's dialect. But, if the meanings of the characters are defined, along with a set of rules on how to use the characters, a speaker of Mandarin, Cantonese, or Hakkacan communicate easily through the medium of writing.
The large influence that Chinese culture has made on its sphere of influence, remains in writing systems of Annamese (Vietnamese), Korean and Japanese over the millenia. Their very names are, in a sense, chinese in origin. (In modern Chinese, Annam = An Nan means Peaceful South; Vietnam = Yue Nan means Remote South; Korea = Kao Li means High Beauty; and Japan = Ri Ben meaning Sun's Origin.) Evidence still survive in old political documents, and in writing today, especially in Japan and South Korea. (Vietnamese converted to an alphabet when the French made it a colony, employing diacritics to note tonal values. Documents were written in psuedo-chinese prior to the french influence.) Evidently the way that these characters are pronounced is very different from that of any modern chinese dialect. Nonetheless, many of those characters adopted retained their fundamental meanings.
Though the pronunciation of these words are not phonetically similar to modern Chinese, they do retain some of the quality of the sounds at the time when they were introduced. This opens the ways to comparing how the differences have amounted over time, and also to figure out the sounds of Chinese in more ancient times.
Chinese script is often thought of as inefficient due the sheer number of them. There are literally thousands of characters. The Qing Emperor Kang Xi commisioned a dictionary of all known chinese characters up till that period, in the early eighteenth century. It totalled some forty eight thousand, grouped into 214 sections, each headed by a radical. A great proportion of this work was found to be just repetitions of a known character but in another form. In everyday chinese, a knowledge of four or five thousand characters were enough. The system used by telegraph operators used about eight thousand, each referenced by a four figure number.
It is not surprising then that it is easy to percieve that characters are a very inefficient means of recording a language. Language reforms started at the beginning of the modern period, with the collapse of the Qing government, has introduced new characters. These are known as simplified characters. It was thought that the language of chinese would oneday be entirely written by a roman alphabet known as the PinYin system. However the persistence of the written word seems unshakeable.