Directionality

Different scripts are written in different directions. The early alphabet could be written in any direction: either horizontal (left-to-right or right-to-left) or vertical (up or down). It could also be written boustrophedon: starting horizontally in one direction, then turning at the end of the line and reversing direction. Egyptian hieroglyph is one such script, where the beginning of a line written horizontally was to be indicated by the direction in which animal and human ideograms are looking.

The Greek alphabet and its successors settled on a left-to-right pattern, from the top to the bottom of the page. Other scripts, such as Arabic and Hebrew, came to be written right-to-left. Scripts that incorporate Chinese characters have traditionally been written vertically (top-to-bottom), from the right to the left of the page, but nowadays are frequently written left-to-right, top-to-bottom, due to Western influences, a growing need to accommodate terms in the Roman alphabet, and technical limitations in popular electronic document formats. The Mongolian alphabet is unique in being the only script written top-to-bottom, left-to-right; this direction originated from an ancestral Semitic direction by rotating the page 90° counter-clockwise to conform to the appearance of Chinese writing. Scripts with lines written away from the writer, from bottom to top, also exist, such as several used in the Philippines and Indonesia.