Translate a Symfony app into Japanese

What Japanese changes in Symfony translation files

Japanese has a single CLDR plural category: other. An ICU string such as {count, plural, one {# order} other {# orders}} becomes {count, plural, other {#件の注文}}. The other branch is mandatory in ICU, so that is the one to look for in the Japanese file. With the older pipe syntax (%count% order|%count% orders), Symfony uses only one form for Japanese.

Plurals go, but counter words arrive: 件 for orders or results, 人 or 名 for people, 個 for objects. %count% users becomes, for instance, %count%人のユーザー.

• Word order: placeholders move. Welcome, %name% becomes %name%様、ようこそ, with the honorific 様 after the name.
• No spaces between words or around placeholders.
• Full-width punctuation: 、 and 。 instead of comma and full stop, brackets as （ ）.
• Register: in a business interface, messages use the polite です／ます form, while buttons stay as short nouns: 保存, 削除, ログイン.

What Manuce returns, and what it does not do

Both Symfony formats, XLIFF and YAML, are supported. You get back the same file: indentation, key order, quotes, comments, line endings, encoding and BOM are preserved; only the values change. In XLIFF, your IDs and notes stay where they were.

Each translated value is compared with the source. If the Japanese output loses a placeholder, say %name% turned into %名前%, or drops a <b> tag, and the mismatch persists, the source value is kept and the report says so. A visible source-language string is better than a rendering error.

Not translated: keys, empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything you have marked as non-translatable. Pricing is based on the words in the values, excluding keys and tags; Japanese is a surcharged language (×1.6 coefficient).

Manuce does not touch your configuration, Twig templates or stylesheets, and does not translate text hard-coded in PHP or Twig. Nor does it produce certified (sworn) translations: terms and conditions intended for legal use in Japan should be reviewed by a qualified professional.

Preparing the source file

1. Extract every string: php bin/console translation:extract --force en fills the source file with keys used in your templates and controllers. A string missing from the file will not be translated.
2. Cover each domain: messages plus any custom domains. Messages for built-in constraints and the Security component already ship in Japanese with Symfony; only your custom validation messages need translating.
3. Keep the ICU suffix: messages+intl-icu.en.xlf must become messages+intl-icu.ja.xlf, otherwise Symfony will not parse {count, plural, …}.
4. Add context: an XLIFF note or YAML comment such as "button label, max 10 characters" helps choose between 送信 and 送信する.
5. Mark what must stay: product names, acronyms, internal codes.

Check the encoding too: UTF-8 is essential for kanji and kana.

Checking the Japanese inside the app

Once the file is renamed messages.ja.xlf or messages.ja.yaml, add ja to enabled_locales and check:

• Syntax: php bin/console lint:xliff translations or lint:yaml translations. In YAML, a half-width colon in an unquoted value breaks the file; the full-width ： does not.
• Gaps: php bin/console debug:translation ja lists missing keys or values identical to the source; compare them with Manuce's report.
• Fonts: use a font stack that covers Japanese (Noto Sans JP or system fonts), or some characters will render as boxes.
• Line breaks: without spaces, browsers break between characters. The CSS rule line-break: strict stops lines starting with 。 or ー.
• Width: Japanese strings often have fewer characters, but each is wider. A Twig |u.truncate(20) may overflow; test buttons and table columns.
• Dates: format_date with the ja locale gives 2025年3月5日. Do not hand-translate date formats.

In practice

1. Run translation:extract to get a complete source file, domain by domain.
2. Upload messages.xx.xlf or .yaml, choose Japanese and a level, and read the free sample.
3. Rename the returned file messages.ja.xlf (or +intl-icu.ja.xlf) and place it in translations/.
4. Read the report, run lint and debug:translation ja, then test fonts, line breaks and widths.