20% of the world population was illiterate in 1998 by the United Nations definition - the inability to read and write a simple sentence in any language. Using a definition of: "age 15 and over can read and write", the U.S. CIA World Factbook estimated in 2007 that the overall world literacy rate was 82%. East Asian and Latin American countries generally have illiteracy rates in the 10 to 15% region while developed countries have illiteracy rates of a few percent.
Traditional definitions of literacy consider the ability to "read, write, spell, listen, and speak. Since the 1980s, some have argued that literacy is ideological, which means that literacy always exists in a context, in tandem with the values associated with that context. Prior work viewed literacy as existing autonomously.
Some have argued that the definition of literacy should be expanded. For example, in the United States, the National Council of Teachers of English and the International Reading Association have added "visually representing" to the traditional list of competencies. Similarly, in Scotland, literacy has been defined as: "The ability to read and write and use numeracy, to handle information, to express ideas and opinions, to make decisions and solve problems, as family members, workers, citizens and lifelong learners.
A basic literacy standard in many societies is the ability to read the newspaper. Increasingly, communication in commerce or society in general requires the ability to use computers and other digital technologies. Since the 1990s, when the Internet came into wide use in the United States, some have asserted that the definition of literacy should include the ability to use tools such as web browsers, word processing programs, and text messages. Similar expanded skill sets have been called multimedia literacy, computer literacy, information literacy, and technacy.
"Arts literacy" programs exist in some places in the United States, Australia, Canada, and Finland.
It is argued that literacy necessarily includes the cultural, political, and historical contexts of the community in which communication takes place.
Although the history of literacy goes back several thousand years to the invention of writing, what constitutes literacy has changed throughout history. At one time, a literate person was one who could sign his or her name. At other times, literacy was measured only by the ability to read and write Latin (regardless of a person's ability to read or write his or her vernacular). Even earlier, literacy was a trade secret of professional scribes, and many historic monarchies maintained cadres of this profession, sometimes—as was the case for Imperial Aramaic—even importing them from lands where a completely alien language was spoken and written.
In the Middle Ages, literacy was measured by the ability to recite passages of scripture. In some societies, this skill was made available only to the clergy, and the ability to read and write might even have been seen as dangerous in the hands of less discerning groups. In medieval Europe, Jews consequently had an edge over the predominantly Christian population because many Jewish males received a basic (religious) education that enabled them to read, write and understand Hebrew, a skill that they also applied in secular life. This skill may be contrasted with the ability to "read" scripture, but—because it is not in the vernacular—not actually knowing what the text says.
In 12th and 13th century England, the ability to read a particular passage from the Bible entitled a common law defendant to the so-called benefit of clergy, which entitled a person to be tried before an ecclesiastical court, where sentences were more lenient, instead of a secular one, where hanging was a likely sentence. This opened the door to lay, but nonetheless literate, defendants also claiming the benefit of clergy, and—because the Biblical passage used for the literacy test was inevitably Psalm 51—an illiterate person who had memorized the appropriate verse could also claim the benefit of clergy.
By the mid-18th century, the ability to read and comprehend scripture (particularly when scripture was in the vernacular) led to Wales having one of the highest literacy rates. This was the result of a Griffith Jones's system of circulating schools, that aimed to enable everyone to read the Bible (in Welsh). Similarly, at least half the population of 18th century New England was literate, perhaps as a consequence of the Puritan belief in the importance of Bible reading. By the time of the American Revolution, literacy in New England is suggested to have been around 90 percent.
The ability to read did not necessarily imply the ability to write. The 1686 church law (kyrkolagen) of the Kingdom of Sweden (which at the time included all of modern Sweden, Finland, and Estonia) enforced literacy on the people and by the end of the 18th century, the ability to read was close to 100 percent. But as late as the 19th century, many Swedes, especially women, could not write.
Although the present-day concepts of literacy have much to do with the 15th century invention of the movable type printing press, it was not until the industrial revolution of the mid-19th century that paper and books became financially affordable to all classes of industrialized society. Until then, only a small percentage of the population were literate as only wealthy individuals and institutions could afford the prohibitively expensive materials. As late as 1841, 33% of all Englishmen and 44% of Englishwomen signed marriage certificates with their mark as they were unable to write (government-financed public education became available in England in 1870). Even today, the dearth of cheap paper and books is a barrier to universal literacy in some less-industrialized nations.
From another perspective, the historian Harvey Graff has argued that the introduction of mass schooling was in part an effort to control the type of literacy that the working class had access to. According to Graff, literacy learning was increasing outside of formal settings (such as schools) and this uncontrolled, potentially critical reading could lead to increased radicalization of the populace. In his view, mass schooling was meant to temper and control literacy, not spread it.
Literacy has also been used as a way to sort populations and control who has access to power. Because literacy permits learning and communication that oral and sign language alone cannot, illiteracy has been enforced in some places as a way of preventing unrest or revolution. During the Civil War era in the United States, white citizens in many areas banned teaching slaves to read or write presumably understanding the power of literacy. In the years following the Civil War, the ability to read and write was used to determine whether one had the right to vote. This effectively served to prevent former slaves from joining the electorate and maintained the status quo. In 1964, educator Paulo Freire was arrested, expelled, and exiled from his native Brazil because of his work in teaching Brazilian peasants to read.
Between 1500 and 1800, the approaches to reading changed as well. Briggs and Burke (2002) give examples of five types of reading changes : The emergence of 'critical reading', as reading was once taken literally; 'dangerous reading', where reading was seen as dangerous in the hands of less educated groups such as women or commoners; 'creative reading', the application of content via the reader's individual paradigm; 'extensive reading', especially seen in the research of a particular topic; and 'private reading', where formatting of texts changed to embrace the notion of browsing and is an aspect of the rise of individualism.
In South Asia, attitudes toward literacy vary by social sector. Many see literacy as associated with schooling and not with everyday life, and some see greater prestige in relying on memorized texts than on being able to read. However, these ideas are slowly on the decline, as modern education diffuses into the region
In much of Africa, literacy is associated with colonialism, whereas orality is associated with native traditions.
Many children experience difficulty when learning to read. Learning to read is difficult because reading requires the mastery of a code that maps human speech sounds to written symbols. Mastering this code is not a natural process, like the development of language, and therefore requires instruction. Reading can be very difficult if students do not get good instruction in this code.
Readers of alphabetic languages must understand the alphabetic principle in order to master basic reading skills. A writing system is said to be alphabetic if it uses symbols to represent individual language sounds, though the degree of correspondence between letters and sounds varies across alphabetic languages. Logographic writing systems (such as Chinese) use a symbol to represent an entire word, and syllabic writing systems (such as Japanese kana) use a symbol to represent a single syllable.
Phonics is an instructional technique that teaches readers to attend to the letters or groups of letters that make up words. A common method of teaching phonics is synthetic phonics, in which a novice reader pronounces each individual sound and "blends" them to pronounce the whole word. Another method of instruction is embedded phonics instruction, used more often in whole language reading instruction, in which novice readers learn a little about the individual letters in words, especially the consonants and the "short vowels." Teachers provide this knowledge opportunistically, in the context of stories that feature many instances of a particular letter. Embedded instruction combines letter-sound knowledge with the use of meaningful context to read new and difficult words.