Translate a WordPress site into Japanese

What Japanese does to a WordPress theme

Japanese mixes three scripts (kanji, hiragana, katakana) and writes without spaces between words. Translated strings are often shorter in character count than English, but each character is wider: “Read more” becomes 続きを読む, “Search” becomes 検索. Buttons rarely overflow, but they do look different.

• Line breaks: with no spaces, the browser can wrap almost anywhere, so a menu item may split mid-word. Check the main menu, footer and widgets on a phone.
• Fonts: many themes load a web font that only covers Latin characters. The browser then falls back to a system font, mixing styles on the same line. Add a Japanese font (Noto Sans JP, for instance) to the stylesheet.
• Italics and capitals: Japanese typography has no italics, and text-transform: uppercase does nothing to kanji. Themes that rely on these for headings lose that visual hierarchy.
• Full-width punctuation: the full stop is 。, the comma 、, quotation marks 「」. A Latin full stop after a placeholder, as in %s., should become %s。.

WordPress strings that need care in Japanese

A few kinds of .po entries behave differently when the target is Japanese.

• Placeholders and word order: Japanese usually puts complements before the verb. “Posted by %1$s on %2$s” becomes roughly %2$s に %1$s が投稿. If the source uses unnumbered %s, the order cannot change safely, so ask the theme developer for numbered placeholders where possible.
• Plurals: Japanese has a single plural category (CLDR other). Strings created with _n() only need msgstr[0]: “%s comment” and “%s comments” both become %s件のコメント. The file header should read nplurals=1; plural=0;.
• Date formats: themes often expose strings such as F j, Y with a “date format” context. Manuce does not translate date formats, so replace them yourself with a Japanese pattern such as Y年n月j日.
• Register: on a business site, full sentences (error messages, form notices, confirmations) are expected in the polite です・ます form, while short labels stay as nouns: 送信 for “Submit”. The free sample lets you check the tone before paying.

What Manuce returns, and what it does not do

Manuce handles theme and plugin .po and .pot files (the ones you open in Poedit or Loco Translate) and XLIFF files exported by WPML.

• You get the same file in the same format: indentation, entry order, quotes, comments, line endings, encoding and BOM are preserved. Only the values change.
• A .pot comes back as a Japanese .po.
• Every translated value is checked against the source: %1$s, <a href="%s"> and <strong> must all survive. If a mismatch persists, the source value is kept and the report says so.
• Not translated: keys (msgid), empty values, URLs, email addresses, numbers, colours, date formats, identifiers and anything marked as non-translatable.

Manuce does not compile the .mo file; Poedit or Loco Translate do it in one step. It does not translate text baked into images or URL slugs, and it does not produce certified (sworn) translations, so legal wording intended for official use in Japan needs an accredited translator. Japanese carries a ×1.6 language coefficient; the count covers words in the source values only, keys and tags excluded.

Preparing the files and checking the result

Before uploading:

• For themes and plugins, use the supplied .pot or regenerate it with Loco Translate so that it contains every current string.
• For pages, posts and menus managed by WPML, export the content to XLIFF with Japanese as the target.
• WordPress uses the locale code ja for Japanese, with no country suffix: a plugin expects files such as my-plugin-ja.po and my-plugin-ja.mo.

After delivery:

• Read the report: strings kept in the source language are usually those where a placeholder or tag could not be matched.
• Compile the .po into a .mo, put it in place and switch the site language to Japanese.
• Fix date formats, check the plural header, then browse the site on a phone: menus, buttons, breadcrumbs and basket if you have one.
• If you sell online to consumers in Japan, the commercial disclosure page required by Japanese law (特定商取引法に基づく表記) is not part of any theme and has to be written separately.

In practice

1. Collect the theme and plugin .po/.pot files and the WPML XLIFF export.
2. Upload them to Manuce, choose Japanese and review the free sample.
3. Download the translated files and the string report.
4. Compile the .po files into .mo with Poedit or Loco Translate and adapt date formats.
5. Check menus, buttons and fonts on mobile before going live.