What word is used by writers of scholarly books it usually has longer sentences and a greater variety words than everyday speech slangs contractions jargon are avoided?

The word that is used by writers of scholarly books is "formal". Formal writing is typically characterized by longer sentences, a greater variety of words, and the avoidance of slang, contractions, and jargon. This type of writing is often used in academic settings, as well as in business and professional contexts.