Translate a Ruby on Rails app into Japanese

What Japanese changes in a locale file

Moving from en.yml (or any source locale) to ja.yml is more than swapping words. Japanese puts the verb last, so interpolation placeholders move. 'Hello %{name}' becomes %{name}様、こんにちは; '%{count} comments' becomes %{count}件のコメント, with no space and a counter word (件 for items, 人 or 名 for people).

• No spaces between words: a stray space around a placeholder shows on screen. %{count} 件 is a common slip.
• Full-width punctuation: comma 、, full stop 。, brackets （）. Exclamation marks, common in Western flash messages, are rare in professional Japanese.
• Register: messages and emails use the polite です・ます form, with keigo when addressing customers; buttons stay short and noun-like: 保存 (Save), 削除 (Delete).
• Three scripts: borrowed technical terms are written in katakana (ユーザー, パスワード), which can lengthen a label you expected to be short.

Japanese is often shorter in character count than European languages, but every glyph is full-width: a button sized to the pixel for 'Submit' may still overflow.

Plurals, dates and validation errors: Rails pitfalls in Japanese

Japanese has a single CLDR plural category: other. The pair one: '%{count} article' / other: '%{count} articles' collapses into one form, %{count}件の記事. Manuce adapts the one/other keys to the target language; you should check that your app follows the same logic. Without Japanese plural rules loaded (such as those shipped with the rails-i18n gem), the Rails I18n backend looks for one when count is 1, so test that case against your ja.yml.

• Date formats: format strings like '%m/%d/%Y' are not translated. The Japanese convention '%Y年%m月%d日' is yours to enter, or to take from rails-i18n.
• Validation messages: errors.format is often '%{attribute} %{message}'. Japanese drops the space to give メールアドレスを入力してください. Placeholders are checked; the space between them is worth reviewing after delivery.
• Models and attributes: activerecord.models.user and activerecord.attributes.user.email feed forms and errors, so they must match the labels in your views.
• _html keys: the tags they contain are compared with the source, just like placeholders.

What Manuce returns, and what it does not do

You upload your locale file; you get the same file back, in Japanese, ready to drop into config/locales/.

• The source root key (en:, fr: and so on) becomes ja:.
• Indentation, key order, quotes, comments, line endings, encoding and BOM are preserved; only the values change.
• Each translated value is compared with the source (%{count}, %{name}, tags). If a mismatch persists, the source value is kept and the report says so.
• Left untouched: keys, empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything marked as non-translatable.
• A report comes with the file: strings translated, strings left as they were, and why.

Manuce does not touch your code: adding :ja to config.i18n.available_locales, choosing a Japanese font or extracting strings hard-coded in .erb views is down to you. Nor does Manuce produce sworn or certified translations: if your Japanese terms and conditions must be legally binding, use a sworn translator. Pricing covers the words in the values only, keys and tags excluded, with the ×1.6 coefficient that applies to Japanese.

Preparing the file and checking the result

1. Gather your strings: anything still hard-coded in views or mailers should go through t('.key') before upload, or it will not be in the file.
2. Replace concatenation (t('hello') + ' ' + user.name) with a %{name} placeholder: in Japanese the name sits elsewhere and usually takes the honorific 様.
3. Add a YAML comment to ambiguous labels ('Open' a folder or a session): comments are kept in the returned file and help pick the right term.
4. After delivery, load ja.yml and test count at 0, 1 and 2, validation messages and email subjects (user_mailer.welcome.subject).
5. Check buttons and line wrapping: with no spaces, browsers may break Japanese between almost any two characters, so make sure a unit like 3件 is not split.

Before paying, the free sample shows one paragraph of your file translated at the chosen level: a good moment to judge the register, polite or more neutral, on your own messages.

In practice

1. Export your source locale file, e.g. config/locales/en.yml.
2. Upload it to Manuce: instant quote on the words in the values, plus a free sample.
3. Choose the level: Professional for an interface aimed at Japanese customers.
4. Download ja.yml and the report, then place the file in config/locales/.
5. Test plurals, validation messages, date formats and layout.