Speech acts that express concern for others and minimize threats to self-esteem ("face") in particular social contexts.
Example,
'Shut up!' is rude, even ruder than 'Keep quiet!'
'Do you think you would mind keeping quiet (Margaret Visser, The Way We Are. HarperCollins, 1994)
“Professor, I was wondering if you could tell us about the Chamber of Secrets.” (Hermione in Harry Potter and the Chamber of Secrets, 2002