CJK characters
Chinese is written almost exclusively in Chinese characters. It requires over 3,000 characters for general literacy, but up to 40,000 characters for reasonably complete coverage. Japanese uses fewer characters — general literacy in Japanese can be expected with 1,945 characters. The use of Chinese characters in Korea is becoming increasingly rare, although idiosyncratic use of Chinese characters in proper names requires knowledge (and therefore availability) of many more characters. However, even today, students in South Korea are taught 1,800 characters.
Chinese characters
When the script was first used in the late 2nd millennium BC, words of Old Chinese were generally monosyllabic, and each character denoted a single word.
Increasing numbers of polysyllabic words have entered the language from the Western Zhou period to the present day.
It is estimated that about 25–30% of the vocabulary of classic texts from the Warring States period was polysyllabic, though these words were used far less commonly than monosyllables, which accounted for 80–90% of occurrences in these texts.
The process has accelerated over the centuries as phonetic change has increased the number of homophones.
It has been estimated that over two thirds of the 3,000 most common words in modern Standard Chinese are polysyllables, the vast majority of those being disyllables.