There are different characteristics that separat the written and spoken forms: 1) Permanency: writing is permanent whereas speaking is not. 2) Process Time: because the written form is permanent, you can go back at your own pace to comprehend whereas the spoken form you have immediate processing time. So if you didn't understand what someone said you would have to have them repeat. 3) Distance: when speaking we are face to face for the most part but in writing distance is different as far as time and space. 4) Orthography: writen form only has graphemes but the spoken form has much more (intonation, tone, volume, ...) 5) Complexity: the message in both can be equally complex but the way they are delivered are different (e.g. spoken form tend to use shorter clauses with more conjunctions whereas the written form has longer clauses with punctuation). 6) Vocabulary: the written form uses much more difficult vocabulary. 7) Formality: written form is generally more formal that the spoken form.