There are usually 40 cells per line and 25 lines per page, on paper 11 inches high by 11.5 inches wide. The meaning of the cells is dependent on context. There are braille codes for all languages, for mathematics and science, and for music. The online Encyclopedia Britannica has more detailed information about the braille code and about Louis Braille, its inventor. Braille also contains equivalents for punctuation marks and provides symbols to show their groupings.
Braille is read by moving the hand or hands from left to right along each line.
Both hands are usually involved in the reading process, and reading is generally done with the index fingers. The average reading speed is about 125 words per minute, but greater speeds of up to 200 words per minute are possible. By using braille, blind people can review and study the written word. They can become aware of different written conventions such as spelling, punctuation, paragraphing, and footnotes. Most of all, blind individuals can have access to a wide range of reading materials - educational and recreational reading and practical manuals.