Modern Chinese has many homophones; thus the same spoken syllable may be represented by many characters, depending on meaning.
A single character may also have a range of meanings, or sometimes quite distinct meanings; occasionally these correspond to different pronunciations.
However, there are a few exceptions to this general correspondence, including bisyllabic morphemes (written with two characters), bimorphemic syllables (written with two characters) and cases where a single character represents a polysyllabic word or phrase.
For example, many additional readings have the Middle Chinese departing tone, the major source of the 4th tone in modern Standard Chinese.
Scholars now believe that this tone is the reflex of an Old Chinese *-s suffix, with a range of semantic functions.
Another common alternation is between voiced and voiceless initials (though the voicing distinction has disappeared on most modern varieties).
This is believed to reflect an ancient prefix, but scholars disagree on whether the voiced or voiceless form is the original root.
The characters used in Japan are distinct from those used in China in many respects.