Give the name of the earliest type of system of writing

(i)Mesopotamians wrote on tablets of clay. A scribe would wet clay and pat it into size he could hold comfortably in one hand .He would then carefully smoothen its surfaces, with the sharp end of the reed cut obliquely, he would press wedge shaped signs on to the clay then dried it in the sun. 
(ii)These were written in 'cuneiform' and the language was Sumerian. Sumerian is the earliest known language of Mesopotamia, which was gradually replaced by Akkadian. Thus, Cuneiform writing in Akkadian language continued till the first century CE.
(iii)The sound that cuneiform sign represented was not a single consonant or vowel, but syllables. Thus, the signs that a Mesopotamian scribe had to learn ran into hundreds and he had to be able to handle a wet tablet and get it written before it dried. 
    Thus, writing was skilled craft but ,more important, it was an enormous intellectual achievement, conveying in visual form the system of sounds of a particular language.