HOW DOES BLIND PEOPLE READ

The Braille system is a method that is widely used by people who are visually impaired to read and write and was the first digital form of writing. Braille was devised in 1825 by Louis Braille, a blind Frenchman. Each Braille character or cell is made up of six dot positions, arranged in a rectangle containing two columns of three dots each. A dot may be raised at any of the six positions to form sixty-four (26) possible subsets, including the arrangement in which no dots are raised. For reference purposes, a particular permutation may be described by naming the positions where dots are raised, the positions being universally numbered 1 to 3, from top to bottom, on the left and 4 to 6 from top to bottom on the right. For example dots 1-3-4 (⠍) would describe a cell with three dots raised, at the top and bottom in the left column and on top of the right column i.e. the letter m. The lines of horizontal Braille text are separated by a space, much like visible printed text so that the dots of one line can be differentiated from the Braille text above and below. Punctuation is represented by its own unique set of characters.

The Braille system was based on a method of communication originally developed by Charles Barbier in response to Napoleon's demand for a code that soldiers could use to communicate silently and without light at night called night writing. Barbier's system of sets of 12 embossed dots encoding 36 different sounds was too difficult for soldiers to perceive by touch and was rejected by the military. In 1821 he visited the National Institute for the Blind in Paris where he met Louis Braille. Braille identified the two major defects of the code: First, by representing only sounds, the code was unable to give the orthography of the words and Second, the human finger could not encompass the whole symbol without moving and so could not move rapidly from one symbol to another. His modification was to use a 6 dot cell — the Braille system — representing all the letters of the alphabet. At first the system was a one-to-one transliteration of French but soon various abbreviations and contractions were developed, creating a system much more like shorthand.

People who are totally blind are absolutely not able to interact with the computer without assistive technologies. In order to overcome this barrier, they mostly use screen reader software and Braille displays. In simple terms, a screen reader system speaks all the information in a human voice which comes on the screen as well as the text which is typed on the keyboard. A Braille display makes the same information appear on a Braille line which blind people can read with their fingers. However a screen reader is much more complicated in practice. It is also important that blind people are able to navigate quickly on the screen and find information as they need it. Therefore, screen reader systems are loaded with functionality which read a portion of the screen according to certain different criteria. The more simple ones would read the current character, the current word or the current line. More complex ones would read the status line of an application, the title bar, a certain window or the current item on the menu as the user navigates.

 A Braille display is usually an addition to a screen reader. It is a small unit which lays by the keyboard and displays one line of information in Braille, mostly the same which the screen read announces with speech. This helps blind people understand the layout of the screen better and read texts which is more difficult to understand with speech. For example more complex tablets or texts which contain words in more than one language, such as dictionaries. The effectiveness of a screen reader greatly determines the effectiveness of blind people on the computer. Long ago screen readers only allowed to read the screen line by line, so people had to hunt for information they needed. Today, practically any piece of information can be assigned with a hotkey. Different hotkeys would announce different information in different applications. For example one hotkey would announce the misspelled word in a Microsoft Application, another would read the current table cell in Internet Explorer etc.