Punctuation marks are symbols that indicate the structure and organization of written language, as well as intonation and pauses to be observed when reading aloud.
In written English, punctuation is vital to disambiguate the meaning of sentences. For example, "woman, without her man, is nothing" and "woman: without her, man is nothing" have greatly different meanings, as do "eats shoots and leaves" and "eats, shoots and leaves". "King Charles walked and talked; half an hour after, his head was cut off" is less surprising than "King Charles walked and talked half an hour after his head was cut off". (For English usage, see the articles on specific punctuation marks.)
The rules of punctuation vary with language, location, register and time and are constantly evolving. Certain aspects of punctuation are stylistic and are thus the author's (or editor's) choice. Tachygraphic language forms, such as those used in online chat and text messages, may have wildly different rules