Register and formality
The locale-specific choice between formal and familiar address, affecting pronouns, verbs, greetings, and how close the product sounds.
What it is
Register is the level of social formality carried by word choice and grammar. French chooses between 'tu' and 'vous'; German between 'du' and 'Sie'. The decision reaches beyond one pronoun into verb forms, greetings, imperatives, honorifics, and how directly the product speaks to the reader. Japanese goes further with keigo, a whole polite register with its own verb forms, and IKEA proved the choice is strategic by addressing German customers as 'du' while the rest of German retail stayed on 'Sie'.
Choose a register for each target locale in the localization style guide before translation starts. Base it on the audience, product category, brand voice, and market expectations, then give examples for buttons, errors, support messages, and email. A locale code alone cannot make this choice for you.
Gotcha: inconsistency sounds stranger than either deliberate choice. A German flow that starts with 'Sie' and ends with 'du' appears to change its relationship with the user halfway through checkout. Do not copy one global rule to every market either: the same brand can need a different level of distance in France, Germany, and Japan.
Ask AI for it
Set the de-DE translation to the formal 'Sie' register. Rewrite every complete message, including buttons, validation errors, support copy, and email, so pronouns, verb forms, greetings, and imperatives stay consistent. Add an XLIFF 2.1 note to each unit stating 'register: formal Sie' and flag any source string whose tone cannot be preserved without context. Do not mix 'du' and 'Sie', and do not change product names or factual claims while adjusting formality.