What are the main differences between spoken English and its written variety?answer in detail
There are several differences, all however, center on complexity.
Vocabulary: In the written variety of English, we tend to be more expressive using the vast vocabularies we have in order to sound sophistocated and mature. In our spoken English, we tend to speak with the intention of being heard and understood, thus our expression drops to a lower level for all listeners' ability to understand.
Structure: Our sentence structures grow more complete and complex in the written word because we have time to edit them. In the spoken word, we are crafting our language on the go and it reflects that. In fact, quite often, we do not even speak with complete sentences.
Rules: In our schools, we teach commonly understood style rules for the written word. For example, we ask students not to use pronouns in professional writing. We prevent them from using contractions. In the spoken word, often no set of rules is employed. In fact, if any, it is something like not using bad language.
Genres: We have multiple genres of writing: narrative, poetry, essay, persuasive, comparative. These are just a few, but our spoken word does not even presume to access a genre unless it is a prepared (therefore written speech). The only things you could consider genre would be different slang lexicon, vernacular, or dialects.