What is the difference between formal and informal diction?
The difference between formal and informal diction is the words that you use. Formal diction is official, business type, and appropriate wording. Informal diction is casual wording.
German has formal and informal forms of address, formal and informal and there's also a difference between singular and plural in the informal forms. Modern English makes no difference. you = du (informal, singular) you = Sie (formal, singular and plural, the s is always capitalized, uncapitalized it can mean she or they, depending on the verb referring to it) you = ihr (informal, plural)