Translate an Android app into Japanese

What Japanese changes in strings.xml

Japanese mixes kanji, hiragana and katakana, puts no spaces between words and uses full-width punctuation (、。). In app strings this has three practical effects.

• Word order. The verb comes last, so placeholders often swap places. "%1$s sent you %2$d photos" becomes %1$sさんから写真が%2$d枚届きました. Without positional arguments that reordering cannot happen.
• Plurals. Japanese has a single plural category, other. Nouns do not change with the number; the counter word carries it: 枚 for photos, 件 for messages or notifications, 個 for objects. "1 message" and "5 messages" are 1件のメッセージ and 5件のメッセージ.
• Register. UI sentences use the polite です／ます form ("保存しました"), buttons a short noun form: 保存, キャンセル, 削除. Casual phrasing feels off; heavy keigo does too.

Punctuation follows suit: no full stop on button labels, 。 at the end of sentences, corner brackets 「」 instead of straight quotes, and a full-width ？ in questions.

Length, line breaks and fonts

A Japanese string usually has fewer characters than its source, but each character is full-width. "Settings" (8 characters) becomes 設定 (2), while a help sentence may take up nearly as much width as before. Check long-text screens, not just buttons.

With no spaces to break on, a TextView may split a word in the middle. From Android 13, android:lineBreakWordStyle="phrase" enables phrase-based breaking that reads more naturally in Japanese; on older versions, leave enough room or keep labels short.

Fonts matter too. A custom Latin font bundled with the app has no kanji, so the system falls back to another typeface and the mix of styles shows. Ideographs shared with Chinese can also render in their Chinese shapes if the device or view locale is not properly set to ja.

What Manuce returns, and what it does not do

You upload res/values/strings.xml; you get back the same file with Japanese values, to be saved as res/values-ja/strings.xml.

• string, string-array and plurals elements are translated; in each plurals block the other quantity, the only one Japanese needs, is written.
• translatable="false" is honoured, and keys, empty values, URLs, email addresses, numbers, colours, date formats and identifiers are left alone.
• Indentation, key order, quotes, comments, line endings, encoding and BOM are preserved; apostrophes and special characters stay escaped the Android way.
• Each translated value is compared with the source: if %2$d or a <b> tag goes missing and the mismatch persists, the source value is kept and the report says so.

The report lists translated strings and those left as they were, with the reason. Pricing counts only the words in values, not keys or tags; Japanese carries a ×1.6 language coefficient.

Manuce does not test the layout on a device, translates only the file you upload (not your Play Store listing or strings hard-coded in Kotlin or Java) and does not decide whether your brand should be written in katakana. It does not provide certified translation.

Preparing the file

• Number your arguments. Replace %s … %d with %1$s … %2$d wherever a string has more than one: Japanese needs to move them.
• Mark what must stay as is. App name, trademarks, codes: translatable="false". If you want a katakana rendering of your brand, add it yourself as a separate string.
• Avoid concatenation in code. "Delete " + name + "?" cannot become 「%1$s」を削除しますか？; use one string with a placeholder.
• Use real plurals. Two strings such as items_one and items_many picked by your code would read identically in Japanese; a plurals block lets Android choose.
• Comment ambiguous strings. Is "Share" a button or a screen title? An XML comment above the key helps your reviewers and stays in the returned file.

Checking the result

• Put the file in values-ja, switch an emulator or device to Japanese and walk through the main screens.
• Test placeholder strings with real values: 0, 1 and 25 items, a long user name, a date.
• Read the report: a string left in the source language often points to a malformed placeholder or tag in the original.
• Look for awkward breaks, such as a particle (は, を, の) stranded at the start of a line.
• Have a Japanese speaker review high-stakes screens: payment, consent, error messages.

For a release build, the Professional or Premium level fits; Essential is enough for an internal test build.

In practice

1. Number your arguments (%1$s, %2$d) and mark non-translatable strings in res/values/strings.xml.
2. Upload the file: the quote appears straight away and a free sample shows the register you will get.
3. Choose a level, pay and download the translated file with its report.
4. Save it as res/values-ja/strings.xml and test the app with the device set to Japanese.