Internationalisation

Every string is a key. Source is US English. The instrument must remain an instrument in every locale: numbers first-class, alerts shortest, rails flipping in RTL, time axes staying chronological.

Ether does not treat translation as a post-pass on English screenshots.

Strings are keys

• Every operator-facing string is an ICU message key. No concatenated sentences ("Welcome, " + name + "!").
• Placeholders are named. Plurals and selects use ICU, not handmade if/else in UI code.
• Do not build sentences by stitching translated fragments. Translators need the whole claim.

Expansion

Design for +40% expansion versus English. Labels wrap; they never clip. Buttons, rails, and badges must survive a longer German or Finnish string without overflowing into the reading.

• Prefer wrapping to truncation. If you truncate, provide the full string (tooltip or expand), not an inaccessible ellipsis.
• Do not size containers to the English word.

Layout and RTL

• Logical CSS properties (margin-inline-start, inset-inline-end, padding-inline). Physical left/right only when the thing is geographic, not directional.
• Rails flip in RTL. Navigation and inspector change sides with the inline direction.
• Time axes stay chronological. A spark and a range axis do not mirror into a reversed timeline. Time reads start → end in the locale’s reading of time, not as a flipped drawing.

Formats

• Use locale formatters for numbers, dates, and lists. Do not hard-code , or . as thousands separators.
• Prose dates in English source: 28 Aug 2026. Other locales use their formatter, not a translated abbreviation of the English pattern unless that is the locale convention.
• Times in the operator’s timezone, labelled.
• Percent, currency, and compact notation go through the formatter. Tabular numerals still apply.

Shortcuts and chrome

• No first-letter shortcuts that assume Latin labels (F for Filter). If a command has a key, the key is assigned, not derived from the translated word.
• Wordmark ETHER is untranslated in every locale.
• Images and the mark have no embedded English. The sweep is language-neutral. Captions are separate strings.

Alerts

Alerts stay the shortest line in every locale. Translators are instructed to keep Alert register clipped: consequence first, then the action. Do not let a polite expansion turn an incident into a paragraph.

Pseudo-localisation

Development builds support pseudo-loc (expanded, marked, accented source strings) so layout and clipping fail in engineering, not in a language drop.

Related

• Writing — US English source rules
• Tone of voice — Alert register
• Terminology — words that must not be replaced with near-synonyms
• Assets — untranslated wordmark, logical layout