Text and style
das Register (formal / informal)
In English: register (formal / informal)
The level of language you choose for a situation. The first decision in German is du (family, friends, children, fellow students) or Sie (adults you do not know, customers, officials). Formal German also prefers the Konjunktiv II for requests, the Präteritum and nominal style.
Example: Kannst du mir helfen? Könnten Sie mir bitte helfen?