A writing system is an organized regular method (typically standardized) of information storage and transfer for the communication of messages (expressing thoughts or ideas) in a language by visually (or possibly tactilely) encoding and decoding (known as writing and reading) with a set of signs or symbols, both known generally as characters (with the set collective referred to as a 'script'). These characters, often including letters and numbers, are usually recorded onto a durable medium such as paper or electronic storage/display, although non-durable methods may also be used, such as writing in sand or skywriting.
The general attributes of writing systems can be placed into broad categories such as alphabets, syllabaries, or logographies. Any particular system can have attributes of more than one category. In the alphabetic category, there is a standard set of letters (basic written symbols or graphemes) of consonants and vowels that encode based on the general principle that the letters (or letter pair/groups) represent phonemes (basic significant sounds) of the spoken language. A syllabary typically correlates a symbol to a syllable (which can be a pairing or group of phonemes, and are considered the building blocks of words). In a logography, each character represents a word, morpheme or semantic unit (which themselves can be pairings or groups of syllables). Other categories include abjads (which is an alphabet where vowels are not indicated at all) and abugidas, also called alphasyllabaries (where vowels are shown by diacritics or other modification of consonants). A system's category can often be determined just by identifying the number of symbols used within the system. Alphabets typically use a set of 20-to-35 symbols to fully express a language, whereas syllabaries can have 80-to-100, and logographies can have several hundreds of symbols.
Most systems will typically have an ordering of its symbol elements so that groups of them can be coded into larger clusters like words or acronyms (generally lexemes), giving rise to many more possibilities (permutations) in meanings than the symbols can convey by themselves. Systems will also enable the concatenation (a "stringing together") of these smaller groupings (sometimes referred to by the generic term 'character strings') in order to enable a full expression of the language. The reading step can be accomplished by the reader purely in the mind as an internal process, or expressed verbally (typically, 'reading aloud'). Historically, writing systems have developed after a spoken language has been established, although the individual symbols used (typically an ideogram) may have preceded the spoken word. A special set of symbols known as punctuation is used to aid in structure and organization of many writing systems and can be used to help capture nuances and variations in the message's meaning that are communicated verbally by cues in timing, tone, accent, inflection or intonation.
A writing system will also typically have a method for formatting recorded messages that follows the spoken version's rules like its grammar and syntax so that the reader will have the meaning of the intended message accurately preserved. Writing systems were preceded by proto-writing, which used pictograms, ideograms and other mnemonic symbols. Proto-writing lacked the ability to capture and express a full range of thoughts and ideas. The invention of writing systems, which dates back to the beginning of the Bronze Age in the late Neolithic Era of the late 4th millennium BCE, enabled the accurate durable recording of human history in a manner that was not prone to the same types of error to which oral history is vulnerable. Soon after, it provided a reliable form of long distance communication. And with the advent of publishing, it provided the medium for an early form of mass communication. Secure written communications were also made more reliable with the invention of encryption.
Writing systems are distinguished from other possible symbolic communication systems in that a writing system is always associated with at least a spoken language. In contrast, visual representations such as drawings, paintings, and non-verbal items on maps, such as contour lines, are not language-related. Some symbols on information signs, such as the symbols for male and female, are also not language related, but can grow to become part of language if they are often used in conjunction with other language elements. Some other symbols, such as numerals and the ampersand, are not directly linked to any specific language, but are often used in writing and thus must be considered part of writing systems.