i18n

name	i18n
description	Fill in missing translations in web-next .po files, add i18n-aware UI labels to components, and ensure translation quality — consistent glossary terminology, correct punctuation/typography per language, proper formality levels, and placeholder preservation. Use when translating UI labels, reviewing translations, managing glossaries, or adding new translatable strings to components.
allowed-tools	Read, Edit, Write, Grep, Glob, Agent, AskUserQuestion

Translation & i18n skill

Fill in missing translations (msgstr "") in all web-next/src/locales/*/messages.po files and ensure every translation meets the quality standards below.

Adding translatable strings to components

Import from ~/lib/i18n/macro.d.ts. Always call useLingui() at the top of the component to get the translation helpers.

Simple text

import { useLingui } from "~/lib/i18n/macro.d.ts";

function MyComponent() {
  const { t } = useLingui();
  return <Button>{t`Save`}</Button>;
}

t works in JSX children, attributes, and any expression context:

<Button title={t`Reply`}>…</Button>
<TextFieldLabel>{t`Content`}</TextFieldLabel>
placeholder={t`Search a language…`}
aria-label={t`Language`}

Variable interpolation

Embed runtime values directly in the template literal:

const { t } = useLingui();
t`Failed to sign out: ${error.message}`
t`To follow ${displayName()}, enter your Fediverse handle.`

Translations with JSX elements (Trans component)

When a translation needs inline JSX (links, bold, components), use the <Trans> component from ~/components/Trans.tsx. Placeholder keys use SCREAMING_SNAKE_CASE:

import { Trans } from "~/components/Trans.tsx";
import { useLingui } from "~/lib/i18n/macro.d.ts";

function MyComponent() {
  const { t } = useLingui();
  return (
    <Trans
      message={t`Verified that this link is owned by ${"OWNER"} ${"RELATIVE_TIME"}`}
      values={{
        OWNER: () => <strong>{actor().name}</strong>,
        RELATIVE_TIME: () => <Timestamp value={verified()} />,
      }}
    />
  );
}

Pluralization

Use i18n._(msg…) combined with plural(). The # symbol is replaced with the count:

import { msg, plural, useLingui } from "~/lib/i18n/macro.d.ts";

function FollowerCount(props: { count: number }) {
  const { i18n } = useLingui();
  return (
    <span>
      {i18n._(
        msg`${
          plural(props.count, {
            one: "# follower",
            other: "# followers",
          })
        }`,
      )}
    </span>
  );
}

Accessing the current locale

Use i18n.locale for locale-aware formatting (e.g., Intl APIs):

const { i18n } = useLingui();
date.toLocaleString(i18n.locale, { dateStyle: "full" })

Extracting messages

Before translating, run the extraction command to ensure .po files are up to date with the latest source code:

cd web-next && deno task extract

This runs @lingui/cli extract, which scans web-next/src/ for translatable strings (t`...`, msg`...`, plural(...)) and updates all web-next/src/locales/*/messages.po files. New strings appear as entries with empty msgstr "".

Run this before starting translation work to pick up any newly added or changed strings.

Workflow

1. Run cd web-next && deno task extract to update .po files.
2. For each locale, read both of these before translating:
   • web-next/src/locales/{locale}/glossary.txt — mandatory terminology
   • web/locales/{corresponding-legacy-locale}.json — reference translations from the legacy stack (locale mapping: en-US → en, ja-JP → ja, ko-KR → ko, zh-CN → zh-CN, zh-TW → zh-TW)
3. Fill every empty msgstr "" with a translation that follows all rules below.
4. After translating, review existing non-empty msgstr entries for rule violations and fix them too.

Glossary enforcement

• Always use the exact term from glossary.txt when the source text contains a glossary term.
• If you encounter a term that should be standardized but is not in the glossary, ask the user via AskUserQuestion whether to add it.
• If the user agrees, add the entry to every locale's glossary.txt in the format term → translation (one per line, sorted alphabetically).

Punctuation & typography

All languages

Rule	Correct	Wrong
Ellipsis	… (U+2026)	...
Em dash	— (U+2014)	--
Casing	Sentence case	Title Case

en-US

• Quotation marks: " " (curly double), ' ' (curly single)
• Standard English punctuation rules
• Use sentence case for buttons, links, labels, headings, tabs, menu items, placeholders, and other UI strings. Do not use title case unless the text is a proper noun, brand name, protocol name, acronym, or another term that is conventionally capitalized. For example, write Create note, Save draft, and Remote follow, not Create Note, Save Draft, or Remote Follow.

ja-JP

• Quotation marks: 「」(single), 『』(double/nested)
• Fullwidth punctuation: 。 、 ！ ？
• No space before/after punctuation

ko-KR

• Quotation marks: 「」(single), 『』(double/nested)
• Period: halfwidth . (not fullwidth 。 — this is Korean standard)
• Comma, exclamation, question: , ! ? (halfwidth, Korean standard)
• No space before punctuation

zh-CN

• Quotation marks: 「」(single), 『』(double/nested)
• Fullwidth punctuation: 。 、 ！ ？
• No space before/after punctuation

zh-TW

• Quotation marks: 「」(single), 『』(double/nested)
• Fullwidth punctuation: 。 、 ！ ？
• No space before/after punctuation

Formality & tone

Locale	Style
ko-KR	합쇼체(~합니다) 기본. 리듬감을 위해 가끔 해요체 허용.
ja-JP	です/ます form for UI text
en-US	Neutral, professional
zh-CN	简体中文标准用语
zh-TW	繁體中文標準用語

CJK-Latin spacing

When Latin characters (English words, brand names, numbers) appear next to CJK characters, follow these language-specific rules:

Locale	Rule	Example
ja-JP	No space — particles attach directly	GitHubリポジトリ, Markdownを使用
ko-KR	Space before Latin text; particles attach to Latin	GitHub 저장소, Markdown을 사용
zh-CN	Space on both sides of Latin text	启用了 ActivityPub 的社交网络
zh-TW	Space on both sides of Latin text	啟用了 ActivityPub 的社交網路

Brand names & proper nouns

Never translate brand names or protocol names. Keep them as-is:

• Hackers' Pub, GitHub, Mastodon, Misskey, Pixelfed
• ActivityPub, Markdown, WebFinger

For “fediverse”, follow glossary — some languages use a localized term (ja-JP: フェディバース, ko-KR: 연합우주) while others keep the original.

Terminal punctuation by UI element

UI element	Punctuation
Button / action label	No trailing punctuation in any language
Menu item	No trailing punctuation
Description / help text	End with period (en: ., ja: 。, ko: ., zh: 。)
Question / confirmation	End with question mark (en: ?, ja: ？, ko: ?, zh: ？)
Title / heading	No trailing punctuation

For English UI elements, combine the punctuation rule with sentence case: Load more, Edit draft, and Permission denied are correct; title-case variants such as Load More, Edit Draft, and Permission Denied are not.

Escape sequences

• Preserve \n line breaks from msgid exactly in msgstr.
• Use \n\n for paragraph breaks (e.g., in email content).
• Never convert \n to literal newlines or vice versa.

Gender-neutral language

• en-US: Use “they/their” for third-person singular when gender is unknown. Prefer second person “you/your” where natural.
• ja-JP: Use honorific “さん” for person references.
• ko-KR / zh-CN / zh-TW: These languages are largely gender-neutral by default; avoid unnecessarily gendered terms.

Placeholder & syntax rules

• Preserve all placeholders ({0}, {1}, #, etc.) exactly as they appear in msgid.
• Preserve ICU MessageFormat syntax (plural, select, selectordinal) exactly—only translate the human-readable parts inside.
• Never translate placeholder variable names or format specifiers.

Quality checklist

Before finishing, verify each translation:

• Glossary terms match glossary.txt exactly
• Punctuation follows the locale-specific rules above
• CJK-Latin spacing follows the locale-specific rules
• Brand names are kept as-is, not translated
• Terminal punctuation matches UI element type
• All placeholders from msgid are present in msgstr
• ICU MessageFormat syntax is valid
• Escape sequences (\n) are preserved
• Formality level matches the locale convention
• Gender-neutral language is used
• Translation is concise and natural for UI context