Complexity is an important part of academic writing . According to Biber, 1998, written language is more complex than spoken language. It contains more precise and concise use of language. At the same time, it has more passives voices than spoken language. Ex: The metropolis has been scorched by the dragon`s fiery breath. - The dragon scorched the metropolis with his fiery breath. Besides, written language is connected to nominalisations which means that written language is focused on nouns more than verbs. A verb becomes into a noun. Ex: We walked for charity. The verb walked has been nominalised to the noun walk. Another main characteristic of written language are attributive adjectives which are very common in academic writing. Ex: The blue sea - The sea is blue.
Examples taken from:
Attributive adjectives http://www.ucl.ac.uk/internet-grammar/adjectiv/xadjv2.htm
Passive voice http://www.unc.edu/depts/wcweb/handouts/passivevoice.html
Nominalisations http://unilearning.uow.edu.au/academic/3b.html
