The earliest forms of writing tended to be marks made on a surface (such as clay tablets or bones). These were simplified drawings that represented an object, such as a women or a broom. Such marks are called ‘pictographs’. Pictographs could later be combined to suggest an idea rather than an object (e.g. woman plus broom means ‘housewife’) – thus creating an ‘ideogram’. Both pictographs and ideograms are examples of ‘thought-writing’.
A major change occurred when ‘sound-writing’ emerged, that is when a written character came to represent a sound, not a thing or an idea. A pictograph depicts an object: a picture of a car would at first simply mean ‘car’. However, the sound of a depicted object could on occasions and over time be used to reproduce the sound of all, or part of, a word. For instance, ‘CAR’ plus ’PET’ would be ‘CARPET’, where the original meanings of the pictographs making up the sound of the word were ignored. This is Rebus writing. The character could stand for the sound of a whole word (verbal), or of a syllable (syllabic), or a single sound (alphabetic). Verbal systems often required thousands of characters, syllabic hundreds, but alphabetic systems usually only needed between twenty and thirty. Many early written languages were a combination of thought- and sound-writing, and some written languages still are (such as Chinese).